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Is sleeping in on weekends bad?

Last updated: October 15, 2026

It can be. Regularly sleeping in at weekends is a sign of 'social jet lag', the gap between your body clock and your weekday schedule. Studies link more social jet lag with a higher BMI and lower wellbeing, and the CDC advises keeping the same schedule every day.

The mechanism

Your body clock adapts slowly. Shifting your sleep by 2 hours at the weekend and back on Monday is a bit like flying across 2 time zones and back every week, which is why researchers call it social jet lag (Wittmann et al., 2006).

The metabolic cost

A large study found that more social jet lag was associated with a higher body mass index, beyond the effect of sleep duration (Roenneberg et al., 2012). These are associations: they do not prove that sleeping in causes weight gain.

Better alternative

If you need more sleep, go to bed earlier rather than getting up much later, and keep your wake time stable. The CDC recommends going to bed and getting up at the same time every day.

Sources

1. Centers for Disease Control and Prevention. CDC — Sleep and Sleep Disorders
2. Wittmann et al., Chronobiology International, 2006. Social jetlag: misalignment of biological and social time
3. Roenneberg et al., Current Biology, 2012. Social jetlag and obesity