Sweat dreams?
While trying to get ripped is an admirable goal, new research reveals that doing it at night might just be muscling into your REM cycle.
High-intensity workouts four hours or less before bed were linked to poorer sleep quality, later bedtimes and a higher resting heart rate.
They were also associated with lower heart rate variability, meaning less variation in the time between heartbeats, which is generally a sign of stress or poor recovery.
All of the markers indicate strenuous exercise that close to lights out puts the body into a heightened state of alertness, hindering the transition to restful sleep.
Strenuous exercise is defined as activities that require a lot of physical effort — typically elevating the heart rate to 70% to 85% of maximum capacity — such as biking uphill, engaging in HIIT or playing sports.
While experts have generally agreed that working out right before bed isn’t good for you, this is the first and most extensive study to illuminate why.
“Intense exercise in the evening can keep the body in a heightened state of alertness, which is why public health guidelines have previously advised against working out too close to bedtime,” lead author Dr. Josh Leota, a research fellow in the School of Psychological Sciences at Monash University in Melbourne, Australia, said in a statement.
“However, findings from controlled laboratory studies are less conclusive, with many suggesting that evening exercise doesn’t necessarily disrupt sleep.”
These studies relied on small sample sizes and laboratory settings, Leota said, and rarely involved exercise that made substantial cardiometabolic demands on the body.
For his research, Leota and his team analyzed data from 14,689 people over the course of one year, which translated to a whopping 4 million nights of information.
Participants wore a health-tracking wristband called WHOOP to monitor their sleep, exercise and heart health.
The findings were adjusted for factors such as gender, age and general fitness level, lending further credibility to the study’s conclusions.
The results were published recently in the journal Nature Communications.
Studies indicate that exercising in general is good for sleep, with some researchers reporting that short, light workouts before bed can help you sleep longer, lower blood sugar levels and potentially live longer.
So, if you do find yourself wanting to work out a couple of hours before bed, Leota suggests choosing “brief low-intensity exercises, such as a light jog or swim, to minimize sleep disruption and allow the body to wind down.”
Or, for added gut health benefits — just take a fart walk.
