Modern lifestyles are marked by a prevalence of sedentary behaviors and physical inactivity, which have been linked to numerous adverse health effects. While regular physical exercise is a well-established countermeasure, exercising in the late afternoon may paradoxically disrupt deep sleep due to increased core body temperature. Inactive and sedentary individuals, who often have impaired autonomic function compared to endurance-trained athletes, may be particularly susceptible to these negative effects, potentially resulting in compromised thermoregulation and exacerbated disruptions to deep sleep, a critical stage of sleep essential for overall recovery. Therefore, this study aims to investigate the impact of aerobic exercise performed in the late afternoon versus morning on: 1) deep sleep and sleep onset latency; and 2) core body temperature and its autonomic regulatory mechanisms on endurance-trained and inactive-sedentary people.

Inclusion Criteria:

• Group "Inactive" :No regular exercise practice (inactive people that don't follow the WHO recommendations) and have sedentary behaviors
• Group "Active": Regular exercise (athletes that are specialized in aerobic exercise, with more than 300 minutes per-week over 6 months and practice at regional level).

Exclusion Criteria:

• Have sleep disorders medically diagnosed or detected by sleep forms cutoffs (clinical insomnia by ISI, severe risk of obstructive sleep apnea by Stop-Bang, bad sleep quality by PSQI.
• Have a diagnosed mental health condition requiring treatment
• Have renal, respiratory, cardiovascular or neuromuscular disease medically diagnosed.
• Be pregnant or breastfeeding

This study is realized only in St-Etienne university Hospital