Abstract
This study sought to investigate the effect of cold ambient temperature on subcutaneous abdominal adipose tissue (SCAAT) lipolysis and blood flow during steady-state endurance exercise in endurance-trained cyclists. Ten males (age: 23 ± 3 years; peak oxygen consumption: 60.60 ± 4.84 ml·kg−1·min−1; body fat: 18.4% ± 3.5%) participated in baseline lactate threshold (LT) and peak oxygen consumption testing, two familiarization trials, and two experimental trials. Experimental trials consisted of cycling in COLD (3 °C; 42% relative humidity) and neutral (NEU; 19 °C; 39% relative humidity) temperatures. Exercise consisted of 25 min cycling at 70% LT and 25 min at 90% LT. In situ SCAAT lipolysis and blood flow were measured via microdialysis. Heart rate, core temperature, carbohydrate and fat oxidation, blood glucose, and blood lactate were also measured. Heart rate, core temperature, oxygen consumption, and blood lactate increased with exercise but were not different between COLD and NEU. SCAAT blood flow did not change from rest to exercise or between COLD and NEU. Interstitial glycerol increased during exercise (p <.001) with no difference between COLD and NEU. Fat oxidation increased (p <.001) at the onset of exercise and remained elevated thereafter with no difference between COLD and NEU. Carbohydrate oxidation increased with increasing exercise intensity and was greater at 70% LT in COLD compared to NEU (p =.030). No differences were observed between conditions for any other variable. Cycling exercise increased SCAAT lipolysis but not blood flow. Ambient temperature did not alter SCAAT metabolism, SCAAT blood flow, or fat oxidation in well-trained cyclists, though cold exposure increased whole-body carbohydrate oxidation at lower exercise intensities.
| Original language | English |
|---|---|
| Pages (from-to) | 145-153 |
| Number of pages | 9 |
| Journal | International Journal of Sport Nutrition and Exercise Metabolism |
| Volume | 34 |
| Issue number | 3 |
| DOIs | |
| State | Published - May 1 2024 |
Funding
We are grateful to the National Strength and Conditioning Association for helping fund this study through the National Strength and Conditioning Association Doctoral Student Research Grant. We also thank Joey Hibbard for assisting with data collection and procedure preparation. Michael J. Ormsbee serves on the scientific advisory board for the Korey Stringer Institute. The other authors declare no conflicts of interest. The authors declare that the results of this study are presented clearly, honestly, and without fabrication, falsification, or inappropriate manipulation. Author Contributions: Bach and Saracino contributed equally to this work. Funding: Christopher W. Bach and Michael J. Ormsbee. Study conception and design: Christopher W. Bach, Michael J. Ormsbee, and Brent C. Ruby. Data collection: Christopher W. Bach, Daniel A. Baur, and Brandon D. Willingham. Data analysis and preparation of the first draft of the manuscript: Patrick G. Saracino. Critical revision and editing of all drafts, and the reading and approval of the final manuscript: All authors.
Keywords
- environmental physiology
- microdialysis
- thermoregulation