When it comes to sleep and exercise the jury is in: Working up a good sweat is an important ingredient for getting a good night’s sleep. When it comes to the timing of that workout, it’s a little more complicated.

AM cardio may mean more deep sleep

When you sleep at night, your blood pressure naturally dips by about 10 to 20 percent. That reduction is good for your heart, and may be one way that your body restores itself when you sleep. Some people with sleep apnea don’t experience this nighttime drop in blood pressure, and, in general, it’s linked with lower sleep quality. An early morning sweat session may provide the ideal blood pressure reduction, as well as maximize deep sleep, compared with midday or evening workouts.

Strength training at any time of day may improve sleep

Lifting weights at different times of day doesn’t seem to affect nighttime blood pressure or the amount of time spent in different sleep stages. But there are a couple of key differences. Those who pump iron in the a.m. tend to fall asleep faster than those who work out later in the day. And those who prefer to do their bench presses or bicep curls at night wake up less frequently during the night and sleep better overall, compared with people who work out earlier in the day. The bottom line: Grab those weights whenever it works best for your day, and you’ll snooze better for it.

Hard workouts might keep you up at night (or they might not)

An all-out workout is about as far from a calming bedtime routine as it gets. It raises your body temperature, speeds up your heart rate, and stimulates your nervous system. Exercising intensely too close to bed, for some people, can lead to interrupted sleep. But for other people, even vigorous exercise just two hours before bedtime has no negative effects on their sleep. One way of thinking about it: An evening workout could raise your body temperature similarly to a warm bath. Just like your body cools off post-bath, making you feel sleepy, a post-workout cooling may also help to set the stage for sleep. The bottom line: Experiment with working out at different times of the day and track your sleep patterns to see which camp you fall into.

Sleeping in can take a toll on your workout regimen (which takes a toll on your sleep)

GIVE THE GIFT OF SLEEP: HEALY WATCH