When you sleep, your body uses all the available water to care for your organs, tissues, and muscles, Pellini explains.
If you're hydrated when you go to bed, the discs in your spine will be larger in the morning since they spent the last seven or so hours absorbing nutrients and water. Lifting too soon will put added pressure on them, which could lead to torn or bulging discs, he says.
On the flip side, if you skimped on water your body will prioritize only your organs—not the tissues or muscles—overnight. When you wake up, your discs will be smaller and less lubricated, reducing shock absorption and support and increasing wear and tear, Pellini says.
The bottom line:
To prime your spine for heavy lifts, have your last eight ounces of the day two hours before bed, then drink another eight ounces when you wake up. Stand as much as possible in the morning—or better yet, walk to the club—so your discs can adjust to being upright. After one hour, you'll be ready to go.
If you need to lift any earlier, Pellini suggests starting with 10 minutes of light cardio, 5 to 10 minutes of isolated joint mobility, and 5 to 10 minutes of workout-specific dynamic warm-ups.
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