Jet Lag and Exercise: When to Train, When to RestPhysical activity is a secondary circadian cue. Morning training advances the clock; late-evening training delays it. Use this on purpose.Day oneA 30–60 minute outdoor walk stacks light and movement without the recovery cost of a hard session. Save the gym for day two.Days two and three50–70 percent of normal intensity. Form goes before fitness on short sleep; injury risk is higher than effort suggests. Skip 1RM tests or sprint work for the first week.Cardio vs strengthEasy aerobic work is the most forgiving option in the first 72 hours. High-intensity intervals have the highest cost and lowest return.Late-evening sessionsHard sessions within three hours of target bedtime cost you the night during adjustment week. Lower intensity, cool shower, dim lights afterward.