Responses of Driver-Athletes to Repeated Driving Stints.

PURPOSE: The purpose of this study was to examine and quantify the effect of repeated driving stints on the physiologic, metabolic, and hormonal responses of three professional endurance driver-athletes. METHODS: Core body temperature, HR, and physiological strain index were recorded during the Rolex 24 Hours of Daytona endurance race using the Equivital Life Monitor system. Blood glucose was monitored continuously during the event using a FreeStyle Libre Pro (Abbott, Alameda, CA). Alpha-amylase and cortisol were sampled immediately before the beginning of a stint and immediately after. RESULTS: First-stint overall and individual driver-athlete responses were similar to those reported in the literature. Later-stint responses diverged from the literature. Reductions in initial core temperature, absence of increases in HR and physiological strain index, and altered glucose and hormonal responses were each observed in the later stint. CONCLUSION: The data support previous research showing that motorsports has a measurable physiological, metabolic, and hormonal effect on the driver-athlete. This study also shows that multiple stints elicit responses that deviate from the published literature on single-stint events. This study is also particularly interesting in that it represents one of the first times that longitudinal data have been gathered on endurance racing driver-athletes.

The Accuracy and Validity of iOS-Based Heart Rate Apps During Moderate to High Intensity Exercise.

People use their smartphones for everything from web browsing to tracking fitness metrics. However, it is unclear whether smartphone-based apps that use photoplethysmography to measure heart rate are an accurate or valid measure of exercise intensity. Purpose was to determine the accuracy and validity of two iOS-based heart rate monitors, Runtastic Heart Rate Monitor and Pulse Tracker PRO by Runtastic (Runtastic) and Instant Heart Rate+: Heart Rate and Pulse Monitor by Azumio (Instant Heart Rate), when compared to the electrocardiogram (ECG) and Polar® T31 uncoded heart rate monitor from moderate to vigorous intensity exercise. Participants were 15 male and female regularly active college students. Pre-exercise heart rate and blood pressure were recorded and then participants exercised on a stationary bike at a pedal rate of between 50-60 rpms. After completing a warm-up stage at 40% of age estimated maximum heart rate (AEMHR), exercise intensity progressed from 50% of AEMHR through to 85% of AEMHR in eight, 5-minute stages. At the end of each stage, and having achieved steady-state, heart rates were recorded from each apparatus. After completing the final stage, participants completed a cooldown at 40% of their AEMHR. Post-exercise heart rate and blood pressure were also recorded to ensure full recovery to baseline. There was a strong positive correlation between the Polar® monitor and the ECG during all stages. However, there were not strong correlations for either of the smartphone-based apps at any time point. Although there were weak correlations between the smartphone-based apps and ECG and Polar®, further studies need to be conducted to determine if inaccuracy is due to user error (finger placement, finger temperature, etc.) or the technology behind the apps.

A Real-Time Case Study in Driver Science: Physiological Strain and Related Variables.

This case study was conducted as an attempt to quantify racecar-driver core body temperature and heart rate (HR) in real time on a minute-by-minute basis and to expand the volume of work in the area of driver science. Three drivers were observed during a 15-lap, 25-min maximal event. Each driver competed in the closed-wheel, closed-cockpit sports-car category. Data on core body temperature and HR were collected continuously using the HQ Inc. ingestible core probe system and HR monitoring. Driver 1 pre- and postrace core temperatures were 37.80°C and 38.79°C, respectively. Driver 2 pre- and postrace core temperatures were 37.41°C and 37.99°C. Driver 1 pre- and postrace HRs were 102 and 161 beats/min. Driver 2 pre- and postrace HRs were 94.3 and 142 beats/min. Driver 1's physiological strain index (PSI) at the start was 3.51. Driver 2's PSI at the start was 3.10. Driver 1 finished with a PSI of 7.04 and driver 2 with a PSI of 3.67. Results show that drivers are continuously challenged minute by minute. In addition, before getting into their cars, the drivers already experience physiological and thermal challenges. The data suggest that drivers are getting hot quickly. In longer events, this represents the potential for severe heat injury. Investigating whether the HRs observed are indicative of work or evidence of a thermoregulatory-associated challenge is a direction for future work. The findings support the value of real-time data collection and offer strong evidence for the expansion of research on driver-athletes.

The case for driver science in motorsport: a review and recommendations.

When discussing sports and the athletes who participate in them, it has long been recognized that fitness is a prerequisite for optimal performance. The goal of training to improve fitness levels in athletes is ultimately to minimize the stress that the body experiences during competition. When it comes to the topic of racecar drivers, however, drivers and their trainers have largely been left to their own devices to figure out the stressors and the areas of specific training focus. Unfortunately, racecar drivers have battled the stereotype that they are not athletes, and with little regard for them as athletes, drivers are seldom the focus of scientific research related to their performance. Like the cars they drive, driver-athletes are complex, but from a physiological perspective. However, unlike the cars they drive, driver-athletes have not been examined, evaluated, and tweaked to the same degree. The purpose of this review is two-fold: first, by examining the available literature, to make the case for new research into the driver's role in the driver-car system (i.e. driver science) and the stresses experienced; second, to make the case for more extensive use of microtechnology in the real-time monitoring of driver-athletes. With the miniaturization of sensors and the advent of portable data storage devices, the prospect of quantifying the stresses unique to the driver are no longer as daunting, and the relative impossibility and difficulties associated with measuring the driver-athlete in real-time no longer need to be as challenging. Using microtechnology in the assessment of the driver-athlete and with a more public discussion and dissemination of information on the topic of driver science, the scientific community has the opportunity to quantify that which has been largely assumed and speculated. The current article will offer the following recommendations: first, rather than examining a singular physiological stressor, to examine the interaction of stressors; second, to examine variables/stressors that are more representative of the changing driver demographics; third, to measure drivers in real-time during actual race events; lastly, to work to develop training programs that more accurately apply to the driver and the stresses experienced. In uncovering this information, there is an opportunity to contribute to racing becoming that much safer, that much more competitive, and that much more comprehensive for the driver, the team, and the sport.

The effects of nicotine on the metabolic and hormonal responses during acute cold exposure.

OBJECTIVE: To examine the effects of nicotine on the metabolic and hormonal responses during acute cold exposure. METHODS: Participants in this study included 6 men and 5 women between the ages of 19 and 25 years. Each subject performed 2 cold-air trials (CATs) consisting of a 30-minute baseline (BASE) period and a 120-minute exposure to 10 degree C air. One CAT was performed after a nicotine (NIC) dosing using a 21-mg transdermal patch, whereas the other CAT was performed after a placebo (PL) treatment. Blood samples for metabolic and hormonal measurements were obtained at the end of BASE and immediately after the cold exposure. RESULTS: When examining the sexes separately, there was no difference in norepinephrine between PL and NIC (P = .066). There was also no difference in epinephrine between PL and NIC in either sex (P = .634). From BASE to 120 minutes of the CAT, there was a significant decrease in cortisol (P = .036), but this response was similar between the 2 treatments (P = .077). Glucose and glycerol concentrations were not different between the PL and NIC treatments. At BASE, nonesterified fatty acid (NEFA) concentration was lower during PL compared with NIC (P = .021); however, at 120 minutes of the CAT, NEFA was greater during PL compared with NIC (P = .035). CONCLUSIONS: During 120 minutes of cold exposure, NIC resulted in alterations in the responses in NEFA, whereas the other blood measurements were not significantly different between the 2 groups.

The effect of cold exposure on the hormonal and metabolic responses to sleep deprivation.

OBJECTIVE: The purpose of this study was to determine the effect of 12 degrees C cold exposure for 180-minutes on the hormonal responses of sleep-deprived individuals. METHODS: Participants underwent 2 cold-air trials: 1 after a normal night of sleep (ie, 6-8 hours) and 1 after 33 hours of sleep deprivation (SDEP). A venous blood sample was taken at baseline and then at 90-and 180-minute cold-exposure time points. Repeated-measures analysis of variance was used to determine significance between a normal night of sleep and SDEP for norepinephrine, epinephrine, cortisol, insulin, thyroid hormones triiodothyronine and thyroxine, glucose, and non-esterifled fatty acids. RESULTS: There was no significant main effect for time, trial, or interaction for insulin, thyroid hormones, epinephrine, cortisol, and glucose (P < or = .05). A significant main effect for time for norepinephrine and non-esterified fatty acids was demonstrated (P < .001). DISCUSSION: The lack of significant differences in the hormonal and metabolic responses to cold exposure combined with SDEP may have been because of an ability of the individual to continue to respond despite the environmental stressor or the physiological effect elicited from cold exposure, thereby possibly masking physiological responses of SDEP. CONCLUSIONS: On the basis of these data, SDEP combined with protracted cold exposure apparently was not a great enough stressor to cause a differential response in the hormonal and metabolic parameters.

Thermal and metabolic responses of sleep deprivation of humans during acute cold exposure.

PURPOSE: This investigation evaluated the effects of 33 h of sleep deprivation on the thermoregulation in 12 male and female subjects (26.6 +/- 6.4 yrs) during 180 min of cold exposure in 12 degrees C air. METHODS: Subjects underwent two cold air trials (CAT): one following a normal night of sleep (i.e., 6-8 h) (CON); and one following 33 h of sleep deprivation (SDEP). Rectal temperature (Tre), mean skin temperature (Tsk), heat production (HP), and tissue insulation (Iti), were measured at 5, 15, 30, and every 30 min thereafter. RESULTS: ANOVA revealed no significant differences (p > 0.05) between CON and SDEP for Tre, Tsk, HP, and Iti. A main effect for time was demonstrated for Tre, Iti, HP, and Tsk. A trial x time interaction for Tre and Tsk (p = 0.021) was demonstrated. DISCUSSION: Significant interactions were demonstrated for Tre and Tsk, but post hoc analysis determined no differences between SDEP and CON. This may have been due to the length of the sleep deprivation, cold stressor, or a combination of the two. There were also no overall differences in HP or Iti between SDEP and CON. Further research in this area is needed to evaluate the effects of sleep deprivation during acute cold exposure.

Nicotine effects on thermoregulatory responses of men and women during acute cold exposure.

INTRODUCTION: Due to the impact of nicotine (NIC) on the physiological processes involved in temperature regulation during cold exposure, it is conceivable that NIC may affect the body's thermoregulatory abilities during a cold stress. Thus, the purpose of this study was to examine the effects of NIC on thermoregulatory responses during acute cold exposure. METHODS: There were six men and six women between the ages of 18 and 25 yr who participated in this study. All subjects were active, apparently healthy smokers. Each subject performed two cold air trials consisting of a 30-min baseline period (BASE) and a 120-min exposure to 10 degrees C air. One cold air trial was performed following a NIC dosing using a 21-mg transdermal patch while the other trial was performed after a placebo (PL) treatment. RESULTS: During the cold air trials, there were no differences in rectal temperature (Tre) or mean skin temperature (Tsk) between the PL and NIC treatments in either sex (p > 0.05). However, in men, heat production (M) was 12% lower (p < or = 0.05) and tissue insulation was 17% higher (p < or = 0.05) during the NIC treatment compared with the PL treatment, while these responses in women were unaffected. In both men and women, finger skin vascular conductance (SVCfin), expressed as a percentage of the BASE value, was higher during the NIC treatment compared with the PL treatment during the cold air trials (p < or = 0.05). Lastly, throughout the cold air trials, there was no difference in thermal sensation between the PL and NIC treatments (p > 0.05). DISCUSSION: In conclusion, although NIC administration resulted in sex-specific alterations in M and tissue insulation during cold exposure, the response in Tre was unaffected.

Age effects on thermal, metabolic, and perceptual responses to acute cold exposure.

INTRODUCTION: Thermoregulatory accidents rank as the sixth leading cause of death among older adults. Therefore, there is an urgency to clarify the influence of age on thermoregulation. This investigation sought to evaluate the influence of age on the thermal, metabolic, and perceptual responses of healthy, physically active, old (OLD) and young (YNG) men during exposure to 12, 18, and 27 degrees C for 120 min. METHODS: There were four old (67.7 +/- 4.6 yr) and four young (26.7 +/- 3.4 yr) adult men who participated. Following a baseline period (30 min), the subjects, wearing only cotton shorts, were moved into an environmental chamber where they remained seated for 120 min or until rectal temperature (Tre) was < or = 35 degrees C. Data were collected for Tre, mean skin temperature (Tsk), oxygen consumption (Vo2), tissue insulation (I), thermal sensation (TS), and heat production (HP). RESULTS: Analysis of variance demonstrated a significant (p < 0.05) time x group interaction for Tre, HP, and I, whereby Tre, HP and I were higher in the YNG vs. OLD. Also, Tsk differed between YNG and OLD with the OLD exhibiting a higher Tsk. TS did not differ, although subjects reported feeling colder with each trial. DISCUSSION: These data suggest that there may be a differential thermoregulatory response between OLD and YNG individuals. The higher Tsk in the OLD suggests a deficit in the peripheral response leading to an increased heat loss over a protracted period of time. This heat loss may contribute to the reduction in core temperature and to the development of hypothermia in the older adult.

Behavioral determinants of healthy aging: good news for the baby boomer generation.

The first of the Baby Boomer generation will officially enter the beginning of old age in 2011 by turning 65. Recent research findings suggest that if the members of this cohort group engage in certain healthy behaviors and thought patterns in their middle years, they will experience a vital, satisfying life in their 70s and beyond. This article reviews the existing literature, including the results of longitudinal studies showing variables that predicted successful aging. Focusing on a lifespan psychology perspective of aging, the authors provide behavioral recommendations for middle age individuals that are likely to prevent disease-related disability, cognitive impairment, and late life depression. These include regular physical exercise, engaging in cognitively stimulating activities, maintaining an optimistic mental outlook, and finding meaning in life. The good news for the Baby Boomers is that there is increasing evidence that their behavior at age 50 will impact how they feel at age 80.