What Exercise Does for Your Body

What happens

• During exercise, your heart pumps more blood, vessels in working muscles widen, and you breathe faster and deeper.
• Working muscles can take in blood sugar even without extra insulin, and stay more sensitive to insulin for a day or so.
• Over weeks, resting heart rate falls, blood pressure and blood sugar can improve, and muscles and bones get stronger.
• Regular activity is linked to lower rates of heart disease, stroke, type 2 diabetes, depression, some cancers and early death.
• Some is better than none: the biggest gains come from going from nothing to a little.

Know the warning signs

• Chest pain or pressure during activity
• Feeling faint
• Being unusually short of breath

Stop. If it doesn't settle quickly, call 9-1-1 or your local emergency number. If it does settle, still get it checked.

Call 9-1-1 or your local emergency number.

How much you need

• At least 150 minutes a week of moderate activity (like brisk walking), or 75 minutes of vigorous activity. Up to 300 minutes brings more benefit.
• Muscle-strengthening activities for your major muscles on 2 or more days a week.
• Sit less, and break up long stretches of sitting.
• Older adults: add balance activities, like tai chi, on 3 or more days a week to help prevent falls.
• Start small and build up. Short bouts count.
• If you have heart disease, diabetes or another long-term condition, talk with your health care provider about what's right for you.

Common questions

How much exercise do I need each week?

The World Health Organization, Canadian and U.S. guidelines recommend at least 150 minutes a week of moderate activity, such as brisk walking, or 75 minutes of vigorous activity, plus muscle-strengthening activities on 2 or more days a week. Doing more, up to about 300 minutes of moderate activity, brings more benefit. If that feels like a lot, start with a little: any amount is better than none.

Do short walks count, or do I need 30 minutes at a time?

Short bouts count. Current guidelines no longer require activity to last at least 10 minutes. A few minutes here and there add up, and even a short walk after a meal can help soften the rise in blood sugar.

Does exercise help if I don't lose weight?

Yes. Blood pressure, blood sugar, fitness and mood can all improve even if your weight doesn't change. In large studies, people who are fit have a lower risk of early death than people who are unfit, whatever their weight.

Transcript

Every time you go for a brisk walk, your body quietly shifts into a higher gear. Your heart, your lungs, your muscles, and even your brain all join in.

And over weeks and years, those small changes add up to a longer, healthier life. Let's see what exercise does for your body, and how much you really need.

So let's follow the body on a brisk walk. Within a minute or so, your heart beats faster, and each beat pushes out more blood.

That blood goes where it's needed most. Blood vessels in your working muscles widen, so more of the flow is sent to your legs.

You breathe faster and deeper, pulling in more oxygen for your muscles, and clearing out the extra carbon dioxide they make.

Your working muscles also pull in sugar from your blood, to burn as fuel. And they have a clever trick.

Usually, a muscle cell needs the hormone insulin to let sugar in. But when a muscle contracts, it moves extra sugar doors to its surface on its own, even without extra insulin.

That's one reason a walk after a meal can help soften the rise in blood sugar. And the effect lingers: for a day or so afterwards, your muscles respond better to insulin.

How brisk is brisk? Try the talk test. At a moderate pace, you can talk, but not sing. At a vigorous pace, you can only say a few words before you need a breath.

Now keep it up for a few weeks, and your body adapts. Your heart pumps more blood with each beat, so at rest, it doesn't need to beat as often.

Your blood vessels get better at widening when they need to, which can help lower blood pressure. And your muscles handle blood sugar better, too.

Muscles get stronger when they work against resistance. And bones respond to weight and pulling forces, which helps keep them strong as you age.

Your brain benefits as well. Regular activity can ease anxiety and low mood, help you sleep better, and help keep your thinking sharp as you get older.

Over the years, it adds up. In large studies, active people have lower rates of heart disease, stroke, type 2 diabetes, depression, and several cancers.

Being active for about a hundred and fifty minutes a week is linked to about a third lower risk of dying early, compared with not being active at all.

Steps count, too. A study of about fifty thousand adults found that more daily steps were linked to a lower risk of early death, levelling off at around six to ten thousand steps a day, depending on age.

So how much do you need? Guidelines from the World Health Organization, Canada and the U.S. agree on the basics.

Aim for at least a hundred and fifty minutes a week of moderate activity, or seventy-five minutes of vigorous activity. Doing more, up to three hundred minutes, brings even more benefit.

On two or more days a week, add activities that work your major muscles, like lifting weights, using resistance bands, or carrying heavy groceries. And try to sit less, breaking up long stretches of sitting.

If you're an older adult, add activities that challenge your balance, like tai chi, or standing on one foot while holding a counter, on three or more days a week. They help prevent falls.

If that sounds like a lot, here's the good news. Some is better than none, and the biggest gains come from going from nothing to a little. Even short bouts of a few minutes count.

Start small, maybe with a ten-minute walk, and build up slowly. If you have heart disease, diabetes or another long-term condition, or you're not sure what's safe, talk with your health care provider.

And while you're active, if you get chest pain or pressure, feel faint, or become unusually short of breath, stop. If it doesn't settle quickly, call 9-1-1 or your local emergency number. If it does, still get it checked.

One common myth is that exercise only helps if you lose weight. In fact, your blood pressure, blood sugar, fitness and mood can all improve, even if the scale doesn't move.

So, to recap. Move more, and sit less. Aim for a hundred and fifty minutes a week. Strengthen your muscles twice a week. And remember, every bit counts.

Now you know what exercise does for your body. And your next walk is a great place to start.

Sources

1. WHO Guidelines on Physical Activity and Sedentary Behaviour (2020)
2. Physical Activity Guidelines for Americans, 2nd edition (2018)
3. Canadian 24-Hour Movement Guidelines for Adults (CSEP, 2020)
4. Paluch AE et al. Daily steps and all-cause mortality: a meta-analysis of 15 international cohorts. Lancet Public Health 2022
5. Richter EA, Hargreaves M. Exercise, GLUT4, and skeletal muscle glucose uptake. Physiol Rev 2013
6. Engeroff T et al. Exercise before and after meals and blood sugar: a meta-analysis. Sports Med 2023
7. Sherrington C et al. Exercise for preventing falls in older people living in the community. Cochrane 2019