In Your 40s
By the time you've reached your forties, one of two things has likely happened: You've found a go-to fitness routine, or you've completely given up on your gym-rat goals. Either way, it's time to shake things up, because this is the time when differences between the fit and unfit really start to show, says Tarnopolsky.
The dips in muscle and bone mass that began in your thirties continue but really ramp up if you don't exercise. Retaining fat-burning muscle is critical to keeping your weight in check. It will not only prevent you from going up a few dress sizes but also help you fight off serious stuff like heart disease, diabetes, arthritis, and cancer.
More: 10 Reasons to Lose 10 Pounds
If you've fallen off the fitness wagon, don't despair—starting again is easier than you think. Your body has built a muscle memory, or physiological blueprint, for all the activities you've ever done. The same process that gets you back on a bike after 20 years can help you jump back into the yoga routine you let slide, says Tarnopolsky.
Even if it has been months or years since you last did it, your muscle fibers remain primed and can fall back on your past experience for support. And while your heart's pumping ability naturally slows in this decade, it's more pronounced in people who are already in peak shape, he says. That means those who haven't reached their max fitness may still see improvements.
One change you're bound to notice in your forties is that recovering from workouts takes a little longer. It's because your levels of muscle-aiding hormones like estrogen and testosterone usually drop slightly during this decade, and cortisol, a stress hormone that can break down muscle, tends to increase, says Tarnopolsky.
More: 6 Nutritional Steps for Workout Recovery
Mitochondria in your cells, which are involved with oxygen consumption and muscle building and repair, also lose capacity as you age, and your muscles become a little stiffer as you accumulate scar tissue and thickening in your connective tissue.
Turn the tide on muscle and bone loss with strength work.
Tarnopolsky has found active 65-year-olds with more leg strength and less body fat than sedentary 20-year-olds. You won't make huge gains to your bone mass, but weight-bearing exercise stresses your bones, which promotes the mineralization that keeps them strong, says Bushman.
More: Why Female Runners Should Strength Train Like Men
Sharpen Your Skills
Bump Up Your Weight Training
Make sure you are lifting weights that are heavy enough to challenge yourself, says Jenkins. Your last few reps of a move should be tough to eke out.
Do More Yoga
It's especially valuable now because it boosts flexibility in the spine and hips, which is integral for good posture (include these 10 Best Yoga Poses in your routine). Plus, Downward Dog and inversions are amazing for your complexion, bringing blood flow to your face. Consider it an anti-aging facial!
It's easy to fall into a workout rut in your forties, says Bushman. A new activity, whether it's a salsa dance class, a bicycle tour, or a surfing lesson, can bolster your enthusiasm and pick up your metabolism. (If you need more ideas, try these 5 Moves Guaranteed to Boost Metabolism
This content originally appeared as Workouts for Women: Lean, Strong, Sexy...For Life on Women's Health.
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Stay in shape in a fitness class.