Heat balance in SHR is impaired during exercise until fatigue in warm environment

Heat balance in SHR is impaired during exercise until fatigue in warm environment Daise N.Q. Cunha 1 , Helton O. Campos 1, 3 , Laura H.R. Leite 2 , Lucas R. Drummond 1 , Cândido C. Coimbra 3 , Antônio J. Natali 1 , Thales N. Prímola‐Gomes 1 . Department of Physical Education, UFV, Viçosa, Brazil 1 . Department of Physiology, UFJF, Juiz de Fora, Brazil 2 . Department of Phvsiology and Biophysics, UFMG, Belo Horizonte, Brazil 3 . To investigate thermal balance in SHR subjected to submaximal exercise until fatigue (SMEF) in warm environment. Male SHR and Wistar rats (WIS) were submitted to SMEF at 60% VO 2max and 5º inclination in thermoneutral (25°C, TE) and warm (32°C, WE) environments. Body (T b ) and tail skin (T tail ) temperatures, and oxygen consumption (VO 2 ), were registered during exercise. Total time of exercise (TTE), workload (W), mechanical efficiency (ME) and heat storage (HS) were determined. SHR‐WE showed higher heat production in comparison to WIS‐WE (from 15‐17 min). Baseline T tail was greater in WE, but demonstrated an equal increase among SHR and WIS in both environments. Animals exercising in the WE had higher T b in comparison to TE (from 4‐17 min), while SHR‐WE showed higher T b in comparison to SHR‐TE after 8 min of exercise. SHR had lower ME compared to WIS in TE and WE. Moreover, SHR‐WE showed higher HS compared to SHR‐TE. In conclusion SHR exhibited an increase in heat production and heat storage during exercise until fatigue in warm environment resulting in aggravated hyperthermia linked to lower mechanical efficiency. We used FASEB Statement of Principles for the use of animals in research. Grant Funding Source : CAPES