Thermoregulatory responses in humans during exercise after exposure to two different light intensities

Zhang, Ping; Tokura, Hiromi

doi:10.1007/s004210050508

Cited by 14 publications

(7 citation statements)

References 24 publications

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“…Core temperature was monitored with a disposable rectal probe (Monatherm, Mallinckrodt Medical, St. Louis, MO, USA) inserted at least 12 cm beyond the anal sphincter before testing (O'Brien et al, 2000;Zhang & Tokura, 1999). Skin temperatures were monitored with skin thermistors (Grant Instruments Ltd, Cambridgeshire) attached to the left side of the body at four sites (chest, forearm, quadriceps, and calf) using adhesive tape.…”

Section: Recovery Strategiesmentioning

confidence: 99%

Effect of cold water immersion on repeat cycling performance and thermoregulation in the heat

Vaile

Halson

Gill

et al. 2008

Journal of Sports Sciences

121

114

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To assess the effect of cold water immersion and active recovery on thermoregulation and repeat cycling performance in the heat, ten well-trained male cyclists completed five trials, each separated by one week. Each trial consisted of a 30-min exercise task, one of five 15-min recoveries (intermittent cold water immersion in 10 degrees C, 15 degrees C and 20 degrees C water, continuous cold water immersion in 20 degrees C water or active recovery), followed by 40 min passive recovery, before repeating the 30-min exercise task. Recovery strategy effectiveness was assessed via changes in total work in the second exercise task compared with that in the first. Following active recovery, a mean 4.1% (s = 1.8) less total work (P = 0.00) was completed in the second than in the first exercise task. However, no significant differences in total work were observed between any of the cold water immersion protocols. Core and skin temperature, blood lactate concentration, heart rate, rating of thermal sensation, and rating of perceived exertion were recorded. During both exercise tasks there were no significant differences in blood lactate concentration between interventions; however, following active recovery blood lactate concentration was significantly lower (P < 0.05; 2.0 +/- 0.8 mmol . l(-1)) compared with all cold water immersion protocols. All cold water immersion protocols were effective in reducing thermal strain and were more effective in maintaining subsequent high-intensity cycling performance than active recovery.

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Section: Recovery Strategiesmentioning

confidence: 99%

Effect of cold water immersion on repeat cycling performance and thermoregulation in the heat

Vaile

Halson

Gill

et al. 2008

Journal of Sports Sciences

121

114

View full text Add to dashboard Cite

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“…In a case report, an average weight loss of 1.5 to 2 kg was noted in three obese women after 6 weeks of 1 hour of bright light therapy without exercise (31). Another study of nine female subjects found that body mass loss after exercise was significantly greater after exposure to bright light therapy (32). These researchers also observed that the exercise‐induced increases of core body temperature and the production of lactic acid were lower in the bright light condition.…”

Section: Introductionmentioning

confidence: 99%

Moderate Exercise and Bright Light Treatment in Overweight and Obese Individuals

Dunai

Novák

Chung

et al. 2007

Obesity

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Obesity. 2007;15:1749 -1757. Objective: Increased physical activity is important given the concern over the growing rates of obesity. The aim of this study is to conduct a controlled investigation of the effects of bright light therapy and exercise on weight loss and body composition in overweight and obese individuals. Research Methods and Procedures: Twenty-five overweight and obese subjects were assigned to 6 weeks of moderate exercise with or without bright light treatment. Outcome measure included changes in body mass and body composition and ratings of mood, seasonality, and sleep. Results: Body weight decreased significantly with exercise in subjects in the light and non-light treatment groups, but the change was not significantly different between the groups. Similar results were found for BMI. With exercise, body fat decreased significantly only in the light treatment group. There was a significant effect of the interaction of group by time on body fat composition, but the group by time interaction failed to reach statistical significance for body weight and BMI. Mood scores improved significantly with exercise in the light group, but no significant changes were noted regarding sleep. Discussion: This preliminary study is the first to show that addition of bright light treatment to a 6-week moderate exercise program can alter body composition by significantly reducing body fat. The reduction in body fat mass is of particular importance, because visceral fat has been particularly implicated as a major factor in the development of the metabolic syndrome. This study is an important step toward finding ways to maximize the effects of exercise.

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“…Two previous studies have involved an examination of the effects of light on body temperature measured at rest and during exercise. Zhang and Tokura [29] exposed participants to bright (5000 lux) light from 06:00 -12:00 hours, and found that core body temperature at the end of a subsequent bout of exercise was significantly lower compared to that in dim light. Aizawa and Tokura [1] also exposed participants to either dim or bright light throughout the morning period and found, again, a significant reduction in body temperature at rest following bright light exposure.…”

mentioning

confidence: 99%

Bright Light and Thermoregulatory Responses to Exercise

et al. 2008

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The thermoregulatory responses to morning exercise after exposure to different schedules of bright light were examined. At 07:00 h, six males ran on two occasions in an environmental chamber (temperature = 31.4 +/- 1.0 degrees C, humidity = 66 +/- 6 %) for 40 min at 60 % of maximal oxygen uptake. Participants were exposed to bright light (10,000 lux) either between 22:00 - 23:00 h (BT (low)) or 06:00 - 07:00 h (BT (high)). Otherwise, participants remained in dim light (< 50 lux). It was hypothesized that BT (low) attenuates core temperature during morning exercise via the phase-delaying properties of evening bright light and by avoiding bright light in the morning. Evening bright light in BT (low) suppressed (p = 0.037) the increase in melatonin compared to dim light (1.1 +/- 11.4 vs. 15.2 +/- 19.7 pg x ml (-1)) and delayed (p = 0.034) the core temperature minimum by 1.46 +/- 1.24 h. Core temperature was 0.20 +/- 0.17 degrees C lower in BT (low) compared to BT (high) during the hour before exercise (p = 0.036), with evidence (p = 0.075) that this difference was maintained during exercise. Conversely, mean skin temperature was 1.0 +/- 1.7 degrees C higher during the first 10 min of exercise in BT (low) than in BT (high) (p = 0.030). There was evidence that the increase in perceived exertion was attenuated in BT (low) (p = 0.056). A chronobiologically-based light schedule can lower core temperature before and during morning exercise in hot conditions.

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Thermoregulatory responses in humans during exercise after exposure to two different light intensities

Cited by 14 publications

References 24 publications

Effect of cold water immersion on repeat cycling performance and thermoregulation in the heat

Effect of cold water immersion on repeat cycling performance and thermoregulation in the heat

Moderate Exercise and Bright Light Treatment in Overweight and Obese Individuals

Bright Light and Thermoregulatory Responses to Exercise

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