|
Exercising too close to bedtime may negatively affect the duration, timing and quality of sleep, according to new research led by Monash University. More strenuous workouts carried out shortly before sleep were associated with greater disturbances to both rest and nocturnal cardiac activity.
Published in Nature Communications, the study revealed that exercising within four hours of bedtime was linked to later sleep onset, reduced sleep duration and quality, a higher resting heart rate, and lower
|
heart rate variability. It is the first and largest study to clearly identify these associations.
The international study analysed data from 14,689 individuals over the course of a year, amounting to four million nights of recorded data. Participants wore a multi-sensor biometric device( WHOOP Strap) to track exercise, sleep patterns, and cardiovascular function.
Researchers from Monash University and WHOOP examined the relationships between evening exercise, exercise
|
intensity, sleep quality, and nocturnal cardiac metrics such as resting heart rate and heart rate variability.
They found that the combination of later exercise and higher exercise strain was consistently linked to delayed sleep onset, shorter and poorer quality sleep, elevated night-time heart rate, and reduced heart rate variability. These results were adjusted for variables such as age, gender, day of the week, season, general fitness, and sleep on the previous night.
High-intensity activities included in the study— such as HIIT( high-intensity interval training), football, rugby, and long-distance running— are known to significantly raise breathing rate, core body temperature, heart rate, and mental alertness.
Lead author Dr Josh Leota, from the Monash University School of Psychological Sciences, said he aimed to shed light on the“ important yet puzzling” link between exercise timing and sleep.
“ Intense evening exercise can keep the body in a heightened state of alertness, which is why public
|
health guidelines have typically advised against it. However, findings from controlled laboratory studies have been inconclusive, often suggesting evening exercise does not necessarily impair sleep,” Dr Leota explained.
“ Such studies are limited by small sample sizes and controlled settings, and they rarely include exercise that generates significant cardiometabolic demand— raising questions about their relevance to real-world conditions.” The new study suggests that individuals looking to improve their sleep may benefit from completing exercise sessions at least four hours before bedtime.
“ If exercising within that four-hour window, lower-intensity activities such as a light jog or swim may be less disruptive and allow the body to unwind,” Dr Leota advised.
Senior author Dr Elise Facer-Childs added:“ Our findings show a clear and consistent relationship— particularly where high cardiovascular strain is involved— between evening exercise and disrupted sleep and recovery markers.”
“ These novel and timely results hold important implications for public health advice regarding the timing, duration and intensity of physical activity. This is especially crucial given that two in three Australian adults report at least one sleep issue, and one in five fail to get the recommended seven or more hours of sleep per night.”
|