Zero exercise is not enough. Going for a walk every day is probably a good thing. And if you're training for a marathon, you'll be on your feet for a couple hours of hard workouts every week. But what is the benchmark for a human being just trying to squeeze enough healthy exercise into their life? Let's break it down.
Fortunately, all the major public health bodies (including the World Health Organisation) are in agreement when it comes to the following guidelines for aerobic exercise:
- 150 minutes per week of moderate intensity exercise like walking, ideally broken up into 30 minutes per day over five days
- 75 minutes per week of vigorous exercise like running, ideally in three 25-minute chunks
- It only counts if you do 10 minutes or more in each session, and you should spread your sessions throughout the week (so, you can't take a single 90-minute spinning class and figure you're done.)
If you're a stroll-around-the-neighbourhood person, go with the first recommendation. If you enjoy hard workouts, but would rather not change into your gym clothes every day, you can just go with the 75 minute recommendation. And feel free to mix and match. Here are some possibilities:
- Walk 15 minutes to and from work every week day (5 x 30 minutes = 150 moderate)
- Go running on Monday/Wednesday/Friday, each for 2-3 miles (3 x 25 minutes = 75 vigorous)
- Take a 90-minute heart-pounding cycling class, and go for a walk after dinner at least a few other days of the week (1 x 90 minutes = 90 vigorous, plus perhaps 3 x 15 = 45 moderate)
- Go for a 30-minute easy bike ride on Monday. Try a 45-minute water aerobics class on Wednesday. Take a short hike on Saturday. Mow the lawn for an hour on Saturday. (30 + 45 + 30 + 60 = 165 moderate)
If you're confused about what counts in each category, the UK's National Health Service has a list of "moderate" and "vigorous" activities here.
If you're pretty athletic, the above won't sound like much. Good news! The World Health Organisation has set a secondary goal for people like you. It's simple: just do double the above. So you can aim for 150 minutes per week of vigorous activity:
- Two of those killer 90-minute classes, Monday and Thursday
- A 4-5km run every weekday
- An hour-long martial arts class three times a week
...or, to meet the requirement with moderate activity, you can stroll for an hour before breakfast each day, the favourite activity of spunky grandmas and grandpas who will probably never die. (To be fair, the recommendations we're talking about are for people up to age 65.)
So, what about an upper limit? There isn't one, from a public health point of view. More is better. (And even if you are doing less than the recommendations, anything is better than nothing.)
That said, it is possible for you as an individual to do more exercise than your body is ready for. Don't jump from a life of occasional strolling to a marathon training plan. And if you are on that marathon training plan and you're feeling worn down, take a break already.
Strength, Flexibility, and More
So far we've been talking about aerobic exercise, which is the kind where you're continuously moving (or, perhaps, doing quick work/rest intervals) and your heart rate is up. But there are other important forms of exercise, too. The WHO and other organisations recommend two days per week of "high intensity muscle strengthening activity," which includes anything where you're thinking in terms of sets and reps. (Three sets of eight to 10 reps is a good structure to start.)
That activity can be anything that challenges your muscles, and where the 10th rep is a lot harder than the first: lifting weights, or resistance band exercises, or bodyweight exercises like push-ups. So if you run three days per week but have time for more, don't just fit in extra runs; try adding two days in the weight room instead.
In addition, the American College of Sports Medicine recommends two other kinds of exercise you might otherwise forget:
- Two to three days per week that include stretching, ideally spending 60 seconds stretching each major muscle group. This can be in a few short stints of 10-30 seconds each.
- Two to three days per week that include neuromuscular training. Think of this as hand-eye coordination and its full-body equivalents. Anything involving balance, coordination, or paying attention to your gait fall into these categories.
Both of these can fit into your other workouts. Stretching works well in a cool-down session after your main workout, or some people prefer to put it into a warm-up. If you're doing functional movements like lunges that challenge your balance and coordination, you're working on neuromuscular fitness.