Lack of sleep= poor workout?

Your fitness routine is in full swing two months into the year: You’re eating right and you’re exercising, but you’re not yet seeing the results you want from your workout.

What’s missing? It might be sleep.

So say an increasing number of studies that show sleep deprivation causing such negative outcomes as weight gain, an increase in overuse injuries, a decrease in muscle mass and a reduction in testosterone (which has a whole host of other negative effects, including low sex drive, depression and bone loss).

“You can have two people who are doing the exact same workout and eating the same good nutrition, but one is seeing huge progress and the other isn’t. A lot of the time, good sleep is the difference,” says Mansur Mendizabal, a personal trainer and kettlebell instructor in Washington.

“Sleep is the only time the body is fully recovering and rebuilding,” he says.

In other words, it’s not enough to take a day or two off from training and slouch on the couch and expect good results. It’s sleep — specifically deep sleep — that is the difference when it comes to such things as muscle recovery, mental acuity and reaction time, another important aspect of sports performance.

“It’s during the deep stages of sleep that all the tissues of the body repair,” says John Broussard, a sports medicine doctor in Washington. “But you have to get into all the stages of sleep in the proper sequence to get those restorative benefits.”

There are four parts of the sleep cycle: Stage 1 (near-awake), Stage 2 (onset of sleep), Stage 3 (deep and restorative sleep) and Stage 4 (deep REM or dream state), which occurs at about 90 minutes into each cycle.