Mental Fatigue: The Cost of Cognitive Loading on Weight Lifting, Resistance Training, and Cycling Performance.

PURPOSE: Mental fatigue (MF) can impair physical performance in sport. We tested the hypothesis that cognitive load alone, and intermixed with standard resistance training, would induce MF, increase rating of perceived exertion (RPE), alter perception of weight lifting and training, and impair cycling time-trial performance. METHODS: This 2-part study employed a within-participant design. In part 1, after establishing leg-extension 1-repetition maximum (1RM), 16 participants lifted and briefly held weights at 20%, 40%, 60%, and 80% of 1RM. RPE and electromyography (EMG) were measured for each lift. During the testing sessions, participants completed cognitive tasks (MF condition) or watched neutral videos (control condition) for 90 minutes before lifting the weights. In part 2, they completed submaximal resistance training comprising 6 weight training exercises followed by a 20-minute cycling time trial. In the MF condition, they completed cognitive tasks before and between weight training exercises. In the control condition, they watched neutral videos. Mood (Brunel Mood Scale), workload (National Aeronautics and Space Administration Task Load Index), MF-visual analogue scale (MF-VAS), RPE, psychomotor vigilance, distance cycled, power output, heart rate, and blood lactate were measured. RESULTS: In part 1, the cognitive task increased lift-induced RPE (P = .011), increased MF-VAS (P = .002), and altered mood (P < .001) compared with control. EMG did not differ between conditions. In part 2, the cognitive tasks increased RPE (P < .001), MF-VAS (P < .001), and mental workload (P < .001), but reduced cycling time-trial power (P = .032) and distance (P = .023) compared with control. Heart rate and blood lactate did not differ between conditions. CONCLUSION: A state of MF induced by cognitive load, alone or intermixed with physical load, increased RPE during weight lifting and training and impaired subsequent cycling performance.

Assessment of opiate modulation of pain and nociceptive responding in young adults with a parental history of hypertension.

This double blind, placebo-controlled study examined the effects of an opiate antagonist, naltrexone, on nociceptive flexion reflex (NFR) thresholds and subjective pain in individuals with and without a parental history of hypertension. Using a repeated measures design, NFR threshold was repeatedly assessed on two testing days after administration of either placebo or naltrexone. Immediately after NFR threshold was determined, participants rated the level of pain experienced during the preceding NFR assessment, and at the end of each session participants' electrocutaneous pain threshold was assessed. Two primary findings were obtained. First, individuals with a parental history of hypertension exhibited attenuated pain sensitivity. Second, endogenous opioid blockade was associated with increased pain ratings in women but with increased pain threshold in men. In sum, the present study did not support a direct involvement of the endogenous opioid system in the attenuated pain sensitivity observed in individuals at increased risk for hypertension.

Factors influencing influenza vaccination uptake in an elderly, community-based sample.

This study investigated predictors of influenza vaccination uptake since the introduction of the policy to target over 65s. Four hundred and forty-four participants completed a cross-sectional structured interview. The predictors of vaccination uptake were: having a doctor or nurse who explained why the vaccination is important and possible side effects; living with others; higher occupational status; and having a car or being able to walk to the GPs rather than reliant on others or public transport. Most participants who had received the vaccination reported having done so in response to reminders or advice from medical professionals. The most common explanations given by those who had chosen not to receive the vaccination were fear of side effects and concerns regarding vaccination efficacy. Current national campaigns and general practitioners' reminder programmes appear to have been successful in improving awareness; however, these results suggest that a more informational campaign, focused on the evidence that the vaccine is efficacious and that side effects are limited, may further improve uptake.

Blood pressure reactions to stress and the prediction of future blood pressure: effects of sex, age, and socioeconomic position.

OBJECTIVE: This epidemiological study examined whether the magnitude of blood pressure reactions to mental stress was associated with future blood pressure and whether the strength of association was affected by sex, age, and socioeconomic position. MATERIALS AND METHODS: Resting blood pressure was recorded at initial baseline and in response to mental stress. Five-year follow-up resting blood pressure data were available for 990 (68%) of the participants; 333 were 23 years old at the time of stress testing, 427 were 43, and 230 were 63. There were 541 women and 449 men; 440 came from manual and 550 from nonmanual occupation households. RESULTS: Systolic blood pressure reactions to stress correlated positively with follow-up systolic blood pressure; no association was found for diastolic blood pressure reactions and follow-up diastolic blood pressure. In multivariate tests, systolic reactivity remained predictive of follow-up systolic blood pressure and accounted for 2.3% of the variance not explained by age, body mass index, and initial baseline systolic blood pressure. Systolic and diastolic reactivity predicted 5-year upward drift in systolic and diastolic blood pressure respectively, accounting for an additional 3.6% and 2.9% of variance, respectively, in multivariate models. The predictive value of reactivity was greater for participants from manual occupation households and tended to be greater for men. CONCLUSIONS: The results of this study indicate that blood reactions to mental stress predict future blood pressure status and the increase in resting blood pressure over time. The magnitude of the prediction appears to vary with socioeconomic position and sex.