Physical activity can counteract some of the negative effects associated with too little or excessive sleep. A study found that an increase in physical activity reduced the mortality risk associated with insufficient or excess sleep.

Exercise and healthy sleep are both important in extending life expectancy. However, the interaction between physical activity and sleep duration in promoting health is not clear.

The main limitation of previous research was that it relied on subjective self-reported sleep patterns and physical activity, which may not be accurate. An accelerometer measures movement, and therefore provides objective and more accurate sleep duration and activity estimations.

Accelerometry was used to examine the combined effect of sleep duration and activity on mortality risk. The study included 92,221 people aged between 40 and 73 wearing an accelerometer bracelet for a week.

Sleep durations of 6-8 hours were considered normal. Sleeping less than 6 was considered short. Sleeping more than 8 is long. The total volume of physical activity was divided into tertiles: low, medium, and high. According to WHO guidelines, physical activity with moderate to vigorous intensity is classified.