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Bright Light and Thermoregulatory Responses to Exercise
| Content Provider | Scilit |
|---|---|
| Author | Atkinson, G. Barr, D. Chester, N. Drust, B. Gregson, W. Reilly, T. Waterhouse, J. |
| Copyright Year | 2007 |
| Description | 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 °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 · $ml^{-1}$) and delayed (p = 0.034) the core temperature minimum by 1.46 ± 1.24 h. Core temperature was 0.20 ± 0.17 °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 °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. |
| Related Links | http://www.thieme-connect.de/products/ejournals/pdf/10.1055/s-2007-965161.pdf |
| Ending Page | 193 |
| Page Count | 6 |
| Starting Page | 188 |
| ISSN | 01724622 |
| e-ISSN | 14393964 |
| DOI | 10.1055/s-2007-965161 |
| Journal | International Journal of Sports Medicine |
| Issue Number | 3 |
| Volume Number | 29 |
| Language | English |
| Publisher | Georg Thieme Verlag KG |
| Publisher Date | 2007-09-13 |
| Access Restriction | Open |
| Subject Keyword | Journal: International Journal of Sports Medicine Sport Sciences Body Temperature Physical Activity Circadian Rhythm |
| Content Type | Text |
| Resource Type | Article |
| Subject | Orthopedics and Sports Medicine Physical Therapy, Sports Therapy and Rehabilitation Sports Science |
