Translational science approaches for food insecurity research.

Food insecurity is a pervasive problem that impacts health and well-being across the lifespan. The human research linking food insecurity to poor metabolic and behavioral health outcomes is inherently correlational and suffers from a high degree of variability both between households and even within the same household over time. Further, food insecurity is impacted by societal and political factors that are largely out of the control of individuals, which narrows the range of intervention strategies. Animal models of food insecurity are being developed to address some of the barriers to mechanistic research. However, animal models are limited in their ability to consider some of the more complex societal elements of the human condition. We believe that understanding the role that food insecurity plays in ingestive behavior and chronic disease requires a truly translational approach, and that understanding the health impacts of this complex social phenomenon requires understanding both its psychological and physiological dimensions. This brief review will outline some key features of food insecurity, highlighting those that are amenable to investigation with controlled animal models and identifying areas where integrating animal and human studies can improve our understanding of the psychological burden and health impacts of food insecurity. In the interest of brevity, this review will largely focus on food insecurity in the United States, as the factors that contribute to food insecurity vary considerably across the globe.

The relationship among disordered eating behavior, power of food scale and sensitization of the reinforcing value of food.

INTRODUCTION: Disordered eating behaviors are a current public health concern since their progression can lead to the development of a full criteria eating disorder. Sensitization to repeated intake of high energy density (HED) foods is associated with excess weight gain over time, but less is known about relationships with assessments of disordered eating. Thus, this study aims to understand how disordered eating behaviors refunlate to the influence of the food environment and sensitization. METHOD: 163 adolescents - 50 % female and 13.2 mean age - were followed for 24 months. Sensitization was assessed by comparing the relative reinforcing value (RRV) of HED food at baseline and after two weeks of daily intake; sensitization was defined as RRV of food after repeated intake. Study participants also completed the EDE-Q, and Power of Food Scale (PFS). We conducted multivariate general linear models to examine these associations. RESULTS: Sensitization status and PFS scores at baseline were positively associated with EDE-Q subscale scores cross-sectionally, but not longitudinally, at baseline and 24 months. We found that sensitization to HED food and higher susceptibility to food cues relates to increased disordered eating behaviors and both at baseline and at 24-months. DISCUSSION: These findings suggest that sensitization to repeated HED food intake and the food environment might be a risk factor for later engagement in disordered eating behaviors. Future studies should address the temporal relationships among these factors and the role that social norms around body weight and weight stigma may play in the development of these behaviors.

A psychobioecological model to understand the income-food insecurity-obesity relationship.

Food insecurity, defined by unpredictable access to food that may not meet a person's nutritional needs, is associated with higher BMI (kg/m2) and obesity. People with food insecurity often have less access to food, miss meals and go hungry, which can lead to psychological and metabolic changes that favor energy conservation and weight gain. We describe a conceptual model that includes psychological (food reinforcement and delay discounting) and physiological (thermic effect of food and substrate oxidation) factors to understand how resource scarcity associated with food insecurity evolves into the food insecurity-obesity paradox. We present both animal and human translational research to describe how behavioral and metabolic adaptations to resource scarcity based on behavioral ecology theory may occur for people with food insecurity. We conclude with ideas for interventions to prevent or modify the behaviors and underlying physiology that characterize the income-food insecurity-obesity relationship.

Restriction and Pressure to Eat Are Associated Cross-Sectionally, But Not Longitudinally, With BMI z-Score in a Longitudinal Cohort Study of Adolescents.

Background: Parents can influence child weight through their use of food parenting practices, although data are limited in adolescents. The purpose of this study was to examine the cross-sectional and longitudinal relationships between BMI z-Score (zBMI) and restriction and pressure to eat in adolescents. Methods: Adolescents (12-14 years of age at baseline; N = 236) had their height/weight measured at baseline and 24 months and their parent completed the Child Feeding Questionnaire. Linear regressions examined relationships between food parenting practices and zBMI. Results: Cross-sectionally, restriction was positively associated with zBMI at both baseline (ß = 0.28, p < 0.001) and 24 months (ß = 0.141, p = 0.039). In contrast, pressure to eat was negatively associated with zBMI at both baseline (ß = -0.30, p < 0.001) and 24 months (ß = -0.31, p < 0.001). Neither restriction (ß = -0.028, p = 0.446) nor pressure to eat (ß = -0.027, p = 0.493) at baseline predicted 2-year changes in zBMI. zBMI at baseline did not predict 2-year changes in either restriction (ß = -0.003, p = 0.965) or pressure to eat (ß = -0.056, p = 0.611). Conclusion: Findings highlight that adolescents perceive moderate levels of restriction and pressure to eat, with levels differing by weight status. These findings suggest that the bidirectional relationships between child weight status and food parenting practices are likely established before adolescence, but persist throughout adolescence. Further longitudinal studies should examine the impact of restriction and pressure to eat early in childhood on weight trajectories into adolescence and adulthood. Clinicaltrials.gov: NCT04027608.

Delay Discounting and the Income-Food Insecurity-Obesity Paradox in Mothers.

Food insecurity, defined as unpredictable access to food that may not meet a person's nutritional needs, is paradoxically associated with higher BMI (kg/m2) and obesity. Research has shown delay discounting, a behavioral economic measure of the preference for immediate rather than delayed rewards, is related to higher BMI, and moderates the relationship between income and food insecurity. Based on this research, we used regression models to test whether delay discounting, consideration of future consequences, and perceived stress were atemporal mediators of the food insecurity-BMI relation in 313 mothers, controlling for demographic variables. A secondary aim was to replicate the finding that delay discounting moderates the relationship between low income and high food insecurity. Results showed that low income was associated with higher food insecurity, and higher food insecurity was associated with higher BMI. Delay discounting was the only variable that was indirectly related to both paths of the food-insecurity-BMI relation. Delay discounting accounted for 22.2% of the variance in the low-income-food insecurity-obesity relation, and the total model accounted for 38.0% of the variance. The relation between low income and food insecurity was moderated by delay discounting. These data suggest that delay discounting is a potential mediator of the relationship between food insecurity and high BMI, which suggests reducing discounting in the future could be a novel target to reduce food insecurity and help people with food insecurity to reduce their excess body weight. Trial Registration. This trial is registered with NCT02873715.

The Influence of Relative Reinforcing Value of Food, Sensitization, Energy Intake and Diet Quality on zBMI Change over Two Years in Adolescents: A Longitudinal Cohort Study.

The relative reinforcing value (RRV) of food and sensitization are associated with zBMI and zBMI change over time, but the mechanisms underlying these relationships is unknown. The purpose of this study was to test the hypothesis that greater RRV and sensitization to HED food is associated with lower diet quality and greater energy intake at baseline and again at 24 months and that these relationships result in greater zBMI gain. The RRV of HED and LED food and dietary intake were measured at baseline and again after 24 months in a cohort of 202 boys and girls of 12-14 years old. The baseline RRV of HED food was associated with lower diet quality and lower energy intake at 24 months. zBMI gain was positively associated with the baseline energy intake but not baseline RRV of HED food or diet quality. However, diet quality moderated the relationship between baseline energy intake and zBMI change, with no difference in zBMI change as a function of energy intake when diet quality was high but significant and opposite relationships with energy intake when diet quality was low. This study suggests that high diet quality can reduce the negative impact of greater energy intake on zBMI change in adolescents.

Reinforcing value of food, enriched home environment, and changes in percent overweight in children.

OBJECTIVE: The decision to eat is often a choice made in the context of food and non-food alternatives. However, no research, to the authors' knowledge, has assessed the combination of the motivation to eat, as indexed by the relative reinforcing value of food (RRVFOOD ), and the enriched home environment, i.e., access to activities that can serve as alternatives to eating on weight gain. METHODS: This study used a cross-sectional design to study how RRVFOOD and the enriched home environment predict percent overweight change over 2 years in 291 children aged 6 to 9 years and of varying socioeconomic status. RESULTS: Results showed that RRVFOOD and access to food were positively associated with baseline percent overweight, and an enriched home environment was negatively related to baseline percent overweight. RRVFOOD and an enriched home environment interacted to predict change in percent overweight. Children with a high relative RRVFOOD and a relatively non-enriched environment showed the greatest relative weight gain. CONCLUSIONS: These results suggest that providing an enriched home environment may reduce the effects of food reinforcement and being motivated to eat on weight gain in childhood, and this represents a novel approach to intervention that can be used to strengthen current behavioral approaches to prevent obesity in children.

Eating Patterns among Emergency Medical Service Providers in the United States: A Qualitative Interview Study.

Emergency medical service (EMS) providers experience demanding work conditions in addition to shift work, which increases risk for nutrition related chronic disease such as metabolic syndrome, diabetes, obesity, and cardiovascular disease. The high stress, emergent, and unpredictable nature of EMS may interfere with healthy eating patterns on and off shift, however little is known about how these conditions impact dietary patterns among EMS providers. This study aimed to understand factors impacting dietary patterns through semi-structured interviews with 40 EMS providers throughout the United States. Interviews were conducted virtually via Zoom video conference. Inductive coding was used to identify themes throughout the interviews. Salient factors mentioned in the interviews included hunger, fatigue, stress, coworker influence, ambulance posting, geographical location, agency policy, and culture. Factors were grouped into 4 domains: physiological factors, psychosocial factors, physical environment, and organizational environment, represented by an adapted version of the social ecological model of health behaviors to include factors influencing eating patterns specific to EMS, which may contribute to overall health. Various barriers to healthy eating exist within EMS, and future studies should explore interventions at each level of our proposed model to improve conditions and reduce nutrition related disease risk in this essential population.

The Effect of Financial Scarcity on Reinforcer Pathology: A Dyadic Developmental Examination.

This study investigated the effects of experimentally manipulated scarcity on the reinforcing value of food (RRVfood) and delay discounting (DD), which, together, create reinforcer pathology (RP) among parents and offspring. A stratified sample of 106 families (53 parent/child aged 7−10 dyads & 53 parent/adolescent aged 15−17 dyads) from high- and low-income households visited our laboratory for three appointments. Each appointment included an experimental manipulation of financial gains and losses and DD and RRV tasks. The results showed that, regardless of food insecurity or condition, children had greater RP (ß = 1.63, p < 0.001) than adolescents and parents. DD was largely unaffected by acute scarcity in any group, but families with food insecurity had greater DD (ß = −0.09, p = 0.002) than food-secure families. Food-insecure parents with children responded to financial losses with an increase in their RRVfood (ß = −0.03, p = 0.011), while food-secure parents and food-insecure parents of adolescents did not significantly change their responding based on conditions. This study replicates findings that financial losses increase the RRVfood among adults with food insecurity and extends this literature by suggesting that this is strongest for parents of children.

The effect of food insecurity and stress on delay discounting across families: a COVID-19 natural experiment.

BACKGROUND: Delay Discounting is the extent to which one prioritizes smaller immediate rewards over larger, delayed rewards. The ability to prospect into the future is associated with better health decision-making, which suggests that delay discounting is an important intervention target for the prevention and treatment of chronic disease. Delay discounting decreases throughout development and stressful experiences, particularly those that accompany poverty, may influence this developmental trajectory. The current study leveraged the COVID-19 pandemic and resulting economic downturn as a natural experiment to understand how changes in food insecurity and psychological stress may associated with changes in delay discounting among parents, adolescents, and children. METHODS: A stratified cohort of families (N = 76 dyads), established prior to the initial pandemic lockdowns, were asked to complete a follow-up survey in the summer of 2020, during reopening. Thirty-seven (49%) families had an older adolescent (aged 15 - 18 years) in the study and 39 (51%) had an elementary aged child (aged 7 - 12 years) in the follow-up study. Both data collection points included measurements of economic position, psychological stress, food security status, and delay discounting. RESULTS: The results showed that pandemic food insecurity was associated with greater stress among parents (ß = 2.22, t(65.48) = 2.81, p = 0.007). Parents, Adolescents, and children significantly differed in their response to psychological stress during the pandemic (ß = -0.03, t(102.45) = -2.58, p = 0.011), which was driven by a trend for children to show greater delay discounting associated with an increase in psychological stress during the pandemic (ß = -0.01, p = 0.071), while adolescents and parents showed no change. CONCLUSIONS: These findings add to the evidence that food insecurity is uniquely stressful among parents with no effects on delay discounting. Despite this, we found no evidence that food insecurity was stressful for child or adolescents. A trend in our data suggested that childhood, as compared with adolescence, may be an important developmental period for the association between stress and delay discounting. Future research should continue the longitudinal investigation of childhood stress and the developmental trajectory of delay discounting to ascertain how these effects may persist in adulthood.

Sensitization of the reinforcing value of high energy density foods is associated with increased zBMI gain in adolescents.

BACKGROUND/OBJECTIVES: Characterizing behavioral phenotypes that predict increased zBMI gain during adolescence could identify novel intervention targets and prevent the development of obesity. The purpose of this study was to determine if sensitization of the relative reinforcing value (RRV) of high (HED) or low energy density (LED) foods predicts adolescent weight gain trajectories. A secondary aim was to test the hypothesis that relationships between sensitization of the RRV of food and weight change are moderated by delay discounting (DD). SUBJECTS/METHODS: We conducted a prospective, longitudinal cohort study in 201 boys and girls with an average zBMI of 0.4, who began the study between the ages of 12 and 14 years and completed the study 2 years later. Participants completed five laboratory visits where the RRV of HED and LED, and DD were assessed at a baseline (visits 1, 2, and 4) and then RRV was measured again after participants consumed a portion of the same HED and LED food for 2 weeks (visits 3 and 5; order counterbalanced). Increases (>1) in the RRV from baseline to post-daily intake were categorized as "sensitization" and decreases (≤1) were categorized as "satiation." Participants returned to the laboratory for follow-up visits at 6, 15, and 24 months to have height and weight taken and to complete additional assessments. RESULTS: Sensitization to HED food was associated with a greater zBMI change over time (ß = 0.0070; p = 0.035). There was no impact of sensitization to LED food or interaction between sensitization to HED and LED food on zBMI change and no moderation of DD on the relationship between HED sensitization and zBMI change (all p > 0.05). CONCLUSION: Our prior work showed that sensitization to HED food is cross-sectionally associated with greater zBMI. This study extends this work by demonstrating that sensitization to HED food prospectively predicts increased zBMI gain over time in adolescents without obesity. Future studies should determine if sensitization can be modified or reduced through behavioral intervention. TRIAL REGISTRATION: Clinicaltrials.gov: NCT04027608.

Alcohol mixed energy drink usage and risk-taking among college students in Western New York State.

Alcohol mixed energy drinks (AmED) may promote excessive alcohol intake and risk-taking among college students. Objective: To understand the relationship between AmED use and risky behavior as well as attitudes and motivations for AmED use. Participants: Undergraduate college students N = 422 (Study 1), N = 37 (Study 2). Methods: Using a mixed-methods approach, we first surveyed undergraduate students about their AmED and alcohol consumption and a series of risk behaviors, self-efficacy, and beliefs (Study 1). We then conducted focus groups within the same population to better understand attitudes, knowledge, and motivations for using AmED (Study 2). Results: Recent AmED use was significantly associated with an increased number of reported binge drinking occasions and self-reported driving while intoxicated events. Our qualitative data analyses revealed two major themes associated with AmED consumption: factors encouraging AmED use and decisions about driving while under the influence of alcohol. Conclusions: These findings add to the literature of beliefs and motivations for AmED use among college students.

The effect of acute and chronic scarcity on acute stress: A dyadic developmental examination.

BACKGROUND: Food insecurity, obesity, and psychological stress are interrelated constructs which are thought to be connected through increased energy intake, but the underlying mechanisms for these relationships remain unclear. The current study used experimental methods to investigate how financial losses may influence acute stress in the context of food insecurity for both parents and offspring. This study also sought to examine the effect of acute stress related to financial losses on the reinforcing value of food (RRVfood) and delay discounting (DD). METHODS: One hundred and six families stratified by both offspring age (53 children aged 7-10, 53 adolescents aged 15-17) and household financial resources, visited our laboratory for three separate appointments. Each appointment included the experimental manipulation of financial gains and losses, saliva samples for cortisol assay, continuous heart rate monitoring, self-rated tension, and computer-based DD and RRVfood tasks. Participants also completed surveys to report perceived life stress level and food insecurity status. RESULTS: Among all participants, financial losses were related to decreased heart rates and increased self-rated tension. Among parents reporting food insecurity, acute financial losses resulted in an increase in cortisol levels. Changes in cortisol, heart rate, and tension were not related to RRVfood or DD. CONCLUSION: Food insecure parents are sensitive to financial losses and respond with an increase in cortisol. However, we found no evidence for a relationship between cortisol and RRVfood or DD. This sensitivity to financial losses did not extend to children or adolescents.

Eating and Physical Activity Patterns in Day and Night Shift EMS Clinicians.

Objective: EMS clinicians work in shifts to provide 24-hour care. Shift work is linked with metabolic disease and over 70% of EMS clinicians report having overweight or obesity. Inability to store food in their vehicles combined with limited overnight dining establishments, and unpredictable job demands leads to reliance on convenience and fast foods. The objective of this study was to describe the eating and physical activity patterns among EMS clinicians on days on and off shift.Methods: EMS clinicians throughout the United States participated in a study involving four 24-hour monitoring periods. Participants wore activity monitors to measure physical activity level and remote food photography was used to collect dietary data on two work days and two days off. Repeated measures analysis of variance was conducted to compare energy and macronutrient intake and activity levels in day and night workers on and off shift.Results: We analyzed data from 39 EMS clinicians (29.7 + 8.5yrs old). Controlling for sex, those working night shifts consumed more kilocalories (p=.037) and total fat (p=.043) compared to day shift workers. Night shift workers had fewer steps (p = 0.045), more sedentary time (p = 0.053), and less moderate activity (p = 0.037) during a shift compared to day workers.Conclusion: Among EMS clinicians, night shift is associated with greater energy intake, and decreased physical activity during shifts. This may contribute to positive energy balance and weight gain overtime, increasing risk for metabolic disease.

The enriched home environment and dietary intake are related to percent overBMI in children.

Longitudinal research suggests that living in a cognitively enriched home environment, in which access to activities including hobbies and books are plentiful, can prevent excess weight gain and obesity in children. In order for the enriched home environment to influence weight it should influence energy and macronutrient intake and/or energy expenditure. To test this hypothesis, we used a cross sectional design to study aspects of the child's enriched home environment along with energy and macronutrient intake. A sample of 158 6-9-year-old children measured between February 2017 - April 2019 in Buffalo, NY were selected from a larger study based on criteria for accurate reporting of energy intake using the Block Kid's Food Frequency Questionnaire. Results showed that the Home Observation for Measurement of the Environment (HOME) subscales enriched environment, parental warmth and an integrated family structure were negatively related to child percent overBMI. Hierarchical regression showed that each of these factors improved variance in child percent overBMI accounted for beyond dietary intake or macronutrients, specifically accounting for a total of 18.2% variance in models controlling for total energy intake. These results provide the first demonstration that characteristics of a child's home environment are associated with lower energy intake and independently associated with percent overBMI beyond knowledge of diet. Enriching a child's home environment by providing alternative activities to eating, improving parental warmth and providing opportunities for parents to interact positively with their children may be novel ways to reduce childhood obesity that should be experimentally tested in future research.

The Relative Reinforcing Value of Cookies Is Higher Among Head Start Preschoolers With Obesity.

The relative reinforcing value (RRV) of food measures how hard someone will work for a high-energy-dense (HED) food when an alternative reward is concurrently available. Higher RRV for HED food has been linked to obesity, yet this association has not been examined in low-income preschool-age children. Further, the development of individual differences in the RRV of food in early childhood is poorly understood. This cross-sectional study tested the hypothesis that the RRV of HED (cookies) to low-energy-dense (LED; fruit) food would be greater in children with obesity compared to children without obesity in a sample of 130 low-income 3- to 5-year-olds enrolled in Head Start classrooms in Central Pennsylvania. In addition, we examined individual differences in the RRV of food by child characteristics (i.e., age, sex, and reward sensitivity) and food security status. The RRV of food was measured on concurrent progressive-ratio schedules of reinforcement. RRV outcomes included the last schedule reached (breakpoint) for cookies (cookie Pmax) and fruit (fruit Pmax), the breakpoint for cookies in proportion to the total breakpoint for cookies and fruit combined (RRV cookie), and response rates (responses per minute). Parents completed the 18-item food security module to assess household food security status and the Behavioral Activation System scale to assess reward sensitivity. Pearson's correlations and mixed models assessed associations between continuous and discrete child characteristics with RRV outcomes, respectively. Two-way mixed effects interaction models examined age and sex as moderators of the association between RRV and Body Mass Index z-scores (BMIZ). Statistical significance was defined as p < 0.05. Children with obesity (17%) had a greater cookie Pmax [F (1, 121) = 4.95, p = 0.03], higher RRV cookie [F (1, 121) = 4.28, p = 0.04], and responded at a faster rate for cookies [F (1, 121) = 17.27, p < 0.001] compared to children without obesity. Children with higher cookie response rates had higher BMIZ (r = 0.26, p < 0.01); and RRV cookie was positively associated with BMIZ for older children (5-year-olds: t = 2.40, p = 0.02) and boys (t = 2.55, p = 0.01), but not younger children or girls. The RRV of food did not differ by household food security status. Low-income children with obesity showed greater motivation to work for cookies than fruit compared to their peers without obesity. The RRV of HED food may be an important contributor to increased weight status in boys and future research is needed to better understand developmental trajectories of the RRV of food across childhood.

An Ecological Perspective of Food Choice and Eating Autonomy Among Adolescents.

Adolescence is an important developmental period marked by a transition from primarily parental-controlled eating to self-directed and peer-influenced eating. During this period, adolescents gain autonomy over their individual food choices and eating behavior in general. While parent-feeding practices have been shown to influence eating behaviors in children, little is known about how these relationships track across adolescent development as autonomy expands. The purpose of this qualitative study was to identify factors that impact food decisions and eating autonomy among adolescents. Using the food choice process model as a guide, four focus groups were conducted with 34 adolescents. Focus group discussion was semi-structured, asking teens about influences on their food choices across different food environments, their involvement with food purchasing and preparation, and perceived control over food their choices. Focus group transcripts were analyzed using deductive and inductive code creation and thematic analysis. This study found six leading influences on adolescents' food choices and identified additional factors with prominence within specific environmental contexts. This study distinguished a broader spectrum of factors influencing adolescent food choice that extend beyond "convenience" and "taste" which have previously been identified as significant contributors. The degree of control that teens reported differed by eating location, occasion, and social context. Finally, adolescents demonstrated various levels of engagement in behaviors related to their eating autonomy. Identifying the emergent themes related to adolescent autonomy was the first step toward the goal of developing a scale to evaluate adolescent eating autonomy.

Consumption of a Variety of Vegetables to Meet Dietary Guidelines for Americans' Recommendations Does Not Induce Sensitization of Vegetable Reinforcement Among Adults with Overweight and Obesity: A Randomized Controlled Trial.

BACKGROUND: Food reinforcement, or the motivation to obtain food, can predict choice and consumption. Vegetable consumption is well below recommended amounts for adults, so understanding how to increase vegetable reinforcement could provide valuable insight into how to increase consumption. OBJECTIVES: We sought to determine whether daily consumption of the Dietary Guidelines for Americans (DGA) recommendations for vegetable intake induces sensitization of vegetable reinforcement in adults with overweight and obesity. METHODS: Healthy adults with a BMI ≥ 25 kg/m2 who consumed ≤1 cup-equivalent of vegetables/day were randomly assigned to a vegetable intervention (VI; n = 55) or an attention control (AC; n = 55) group. The VI consisted of the daily provision of vegetables in the amounts and types recommended by the DGA (∼270 g/day) for 8 weeks. Participants were followed for an additional 8 weeks to assess sustained consumption. Compliance was measured weekly by resonance Raman light-scattering spectroscopy (RRS). Vegetable reinforcement was tested at weeks 0, 8, 12, and 16 using a computer choice paradigm. RESULTS: In the VI group, RRS intensity increased from week 0 to 8 (from 22,990 to 37,220), returning to baseline by week 16 (27,300). No change was observed in the AC group. There was no main effect of treatment (P = 0.974) or time (P = 0.14) and no treatment x time interaction (P = 0.44) on vegetable reinforcement. There was no moderating effect of sex (P = 0.07), age (P = 0.60), BMI (P = 0.46), delay discounting (P = 0.24), 6-n-propylthiouracil taster status (P = 0.15), or dietary disinhibition (P = 0.82) on the change in vegetable reinforcement. CONCLUSIONS: These findings suggest no effects of the provision of a variety of vegetables to meet DGA recommendations for 8 weeks on vegetable reinforcement and highlight the difficulty in increasing vegetable consumption in adults. This trial was registered at clinicaltrials.gov as NCT02585102.

The requirement for physical effort reduces voluntary cooling behavior during heat exposure in humans.

We tested the hypothesis that cool-seeking behavior during heat exposure is attenuated when physical effort is required. Twelve healthy adults (mean(SD), 24(4) years, four women) underwent three experimental trials during two hours of exposure to 41(1) °C, 20(0)% relative humidity in which subjects undertook intermittent exercise alternating between seated rest and cycling exercise at ~4 metabolic equivalents every 15 min. In all trials, subjects wore a water perfused suit top. In the control trial (Control), no water perfused the suit. In the other trials, subjects were freely able to perfuse 2.1(0.2) °C water through the suit. In one cooling trial, subjects received two minutes of cooling by pressing a button (Button). The other cooling trial permitted cooling by engaging in isometric handgrip exercise at 15% of maximal grip strength (Handgrip), with cooling maintained throughout the duration the required force was produced or until two minutes elapsed. In both Button and Handgrip, a one-minute washout proceeded cooling. Core temperature increased over time in all trials (P<0.01) and there were no differences between trials (P = 0.32). Mean skin temperature at the end of heat exposure was lowest in Button [34.2(1.5) °C] compared to Handgrip [35.6(0.8) °C, P = 0.03] and Control [36.9(0.7) °C, P<0.01]. The total number of behaviors [8(3) vs. 10(5), P = 0.04] and cumulative cooling time [850(323) vs. 1230(616) seconds, P = 0.02] were lower in Handgrip compared to Button. These data indicate that when physical effort is required, the incidence and duration of cooling behavior during heat exposure is attenuated compared to when behaving requires minimal physical effort.