Hey, active women of a certain age: The good news is that you’re probably going to weather menopause better than your sofa-bound sisters. The bad news is that “the change of life” doesn’t just affect your mood and your lady parts — it also drags down your race times.

Menopause is when the monthly waves of estrogen and other hormones that women have been surfing since puberty finally ebb for good. Periods cease, of course. But all kinds of other biological processes change as well, including some that affect athletic performance.

Combine that with other age-related decline, and you find that your body is a different machine from the one that glided through your 20s and 30s. You’re still an athlete; you just have to figure out your new normal.

“Just because you hit a certain age, your body doesn’t stop,” said Stacy T. Sims, a nutrition scientist and physiologist in New Zealand who has studied women’s performance for 25 years.

“The fitter you are, the less of a problem these are. When you are competing, that’s when you really feel them, because you are, like, ‘What is going on?’ But when you’re a general woman and you’re keeping fit, then all these things are” easier to handle.

But what if you’re not very fit right now?

“It is definitely not too late — that’s the greatest thing about this,” said Monica Serra, a research scientist at the VA Maryland Health Care System who has written about post-menopausal competitive athletes. “If you start exercising, you can build your bone mass, you can build your lean mass, you can lose the fat mass, you can improve the quality of your muscle. . . Research says people who exercise have a better quality of life.”

Major changes that occur during menopause

Sleep quality suffers

Sixty-one per cent of post-menopausal women report insomnia symptoms, according to the U.S. National Sleep Foundation. Many things conspire to disrupt sleep: the decline of estrogen and progesterone, which help you fall and stay asleep; a dearth of melatonin, which regulates body temperature for sleep; hot flashes and night sweats, which wake you up; and the stress hormone cortisol, which estrogen helps control.

But: “Physically active people have better sleep patterns,” Serra said, which is good because a lot of muscle recovery and rebuilding occurs during sleep. Exercise early in the day promotes better sleep. Sims recommends keeping your bedroom cool and trying a small, frosty glass of tart cherry juice before bed to help cool your core and boost natural production of melatonin.

The engine slows

Aerobic capacity, which is your cardiovascular system’s ability to convert oxygen to energy, can drop 5 to 9 per cent each decade beginning in your 30s. (This happens to men as well.) Much of this is because your heartbeat slows a little each year. That means oxygen-rich blood is being pumped to working muscles a little less often.

But: Athletes of all ages have better aerobic capacity and blood volume than people who don’t exercise.

Heat is harder to handle

During hot flashes and whenever the body begins to get too warm, blood rushes to the skin surface to off-load heat — which is annoying for athletes, who’d prefer that the blood feed working muscles. In older adults, sweating, a key part of cooling, begins later in a workout. As if that’s not enough, the thirst mechanism dulls with age, so dehydration is more likely.

But: Good hydration and a little bit of caution can keep you from danger. And for 92 per cent of women who get them, hot flashes will go away.

‘Menopot’ happens

Older women aren’t as efficient at processing carbohydrates, so they tend to store the excess as fat. And they tend to store fat in their bellies rather than in hips and thighs as they did when they were younger. This visceral fat is associated with higher risk of heart disease and diabetes.

But: Studies show that women who exercised four to five times a week have less total body fat than sedentary women of the same height and weight, Serra said. And their visceral fat stores were similar to sedentary women a third their age.

Your stomach rebels

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Women become less efficient at processing carbohydrates, so athletes may find that their beloved bagels and pasta can send blood-sugar levels soaring. In particular, the ability to digest fructose in processed foods declines. So energy gels may suddenly cause midrace GI issues.

But: Eating more fruit and whole grains and less processed sugar can keep stomachs and blood sugar steadier. (Fructose in whole fruit is not a problem.) Look for race-day food that doesn’t contain added fructose.

Bones get thinner

Oestrogen works with calcium and vitamin D to strengthen bones. In the five to seven years after menopause, a woman’s bones can lose up to 20 per cent of their density, Sims said.

But: Athletes start out with denser bones because weight-bearing activity (running, walking, tennis, etc.) puts stress on bones, which spurs the body to strengthen them. Regular strength training and a diet rich in bone-building nutrients — fish and yogurt are good choices — can shore up key areas such as hips and spine.

Flexibility decreases

Age makes all of us less flexible, which means a greater risk for muscle pulls and strains. Runners get very tight hamstrings. People who sit a lot get tight hip flexors and lazy glutes, which can alter gait and range of motion.

But: A little effort can make a huge difference. The American College of Sports Medicine recommends flexibility exercises two or three times a week while muscles are warm, such as after a workout or bath.

Muscles shrink

Testosterone and other growth hormones plunge along with oestrogen, so building and maintaining muscle is tougher. Fat begins to marble the tissue, reducing its ability to generate power. The more muscle you have, the more calories you burn, even at rest.

But: Exercise will help you keep muscle and build more. Strength training, interval training and consuming protein within half an hour of hard exercise will help, Serra said.

Mojo wanes

Fluctuating levels of oestrogen can make you cranky, edgy and even at risk for depression until brain chemistry stabilizes after menopause. “Brain fog” can make it harder to concentrate and remember things, and sleep problems make you tired.

But: Exercise is a known stress reliever and mood booster. Research has found that people who exercise are better able to deal with the ups and downs of aging, Serra said. “You feel better about yourself because you’re accomplishing what you can . . . and that makes you more able to deal with these other stressors, both physical and mental, in your life.”