Physical activity: how much is enough?

We all know physical activity is good for us – it decreases our blood pressure, improves our cholesterol, makes us stronger, improves our mood, reduces our risk of disease and has dozens of other proven benefits.

But how much activity do you really need? And is there a level that is "good enough?"

How much physical activity is recommended?

"If we're talking cardio, we're looking at 150 minutes per week," says Kelsey Bos, disability case manager at Manitoba Blue Cross. Certified with the Canadian Society for Exercise Physiology (CSEP), Bos works with injured and sick clients to help them get better and back to work.

On average, the CSEP recommends 30 minutes of cardio activity, five times a week. It can be broken up in smaller portions, as long as each session lasts at least 10 minutes, Bos says.

Why not shorter sessions?

"It's going to take a few minutes to get your heart rate up to where you want it to be to see the benefits," Bos says. However, getting up and moving at all, even if it's just for a few minutes, is better than remaining sedentary, she adds.

Doing less than 150 minutes per week doesn't mean you're not going to see benefits – but it's an ideal goal, Bos says.

However, it's not just about how many minutes per week, but also the type of activity. As the saying goes, variety is the spice of life.

"You shouldn't be doing the same exercise all the time," she says. "Our body basically has a memory. So, if we do the same workout every day, we notice that our body actually starts to remember the exercises and knows exactly what is coming next." Doing the same exercises every day is still beneficial to overall health, but it offers diminishing returns compared to a varied regime.

Heart rate, perceived exertion and the "talk" test

Exercise is all about getting the heart thumping and the blood pumping. But how do you measure your ideal heart rate?

Bos provides a simple formula – 220 minus your age is an accurate approximation of your maximum heart rate. The ideal range in which your heart rate should fall during exercise is between 60 and 85 per cent of that max rate.

For example: a 30-year-old would subtract 30 from 220, resulting in a max heart rate of 190 beats per minute. Sixty per cent of 190 is 114, and 85 per cent is 161.5 – meaning a 30-year-old would want their heart rate to land between 114 and 162 beats per minute during exercise.

If you're wanting a simpler way to tell if your heart rate is where it should be, Bos recommends the "talk" test. If, while exercising, you have no problem talking, you may want to exert yourself more. If you're barely getting out a word before gasping, you may not want to push yourself too much harder. Finally, Bos recommends the Rate of Perceived Exertion. On a scale of zero to 10 – zero being very little effort and 10 being the most exhausted you've ever been – Bos recommends your exercise lands you between a six and an eight.

Strength training

While cardio is vital, it's not the only exercise you should be doing.

"Strength training is good, because we want to be able to do our active daily living tasks, and we should have some sort of muscle mass to work with," Bos says. She recommends exercising each muscle group (e.g. chest, legs) one to three times per week, leaving 48 hours before exercising the same group again. For instance, if you do an upper-body workout on Monday, you wouldn't want to do the same workout Tuesday, because your body hasn't had enough time to rest and repair itself. Bos notes that strength training is not included in the 150 minutes of recommended weekly exercise.

"With strength training, it's not by time – it's by reps (repetitions) and sets," Bos says. "We usually say anywhere between the eight to 15 reps, one to three sets."

Keep up your flexibility

How often should we be stretching?

"We should be doing it every day," Bos says. The best time to stretch is after exercise, while you're cooling down. "We don't want to be doing static stretching at the very beginning before we do all our exercises, because our muscles aren't even warmed up," she adds. Static stretching before your muscles are warmed up can increase your risk of injury.

It's also important to warm up before you exercise or stretch. Getting the blood flowing before you start will help prevent injury and maximize your benefits.

This may sound like a lot. But it's important to remember that you don't need to jump in all at once. Simply trying to get more exercise in when you can and starting slow can still improve your health and well-being.

If you're already regularly active, try to push yourself. Try new exercises, increase your heart rate or work other muscle groups. Keeping things fresh will help you build on a solid foundation and ensure you see improved benefits for years to come.

To learn more about physical activity guidelines, visit the CSEP website.