How much exercise is enough? Most people know that regular physical activity is good for health, but many aren’t sure what sort of exercise they should do, or how much. The aerobic physical activity guidelines quoted by health departments and charities are published by the World Health Organisation, based on research by the American College of Sports Medicine (ACSM) and are as follows:
WHO minimum guidelines for aerobic physical activity for adults aged 18-64
Adults aged 18–64 years should do at least 150 minutes of moderate-intensity aerobic physical activity throughout the week, or do at least 75 minutes of vigorous-intensity aerobic physical activity throughout the week, or an equivalent combination of moderate- and vigorous-intensity activity.
What do moderate intensity and vigorous intensity mean?
Exercise intensity can be assessed by heart rate (see below), but as a rough guide:
Moderate intensity physical activity
This would be anything which you need to put a bit of energy into and makes you a bit warmer. This can be cleaning the house or car, gardening or walking at a normal pace, for example.
This means activities in which you get very warm, find it more difficult to hold a conversation and may be aware of your heart beating.
Monitoring your heart rate
You can get a better idea of how hard you’re working by checking your pulse rate. It’s best if you’ve got a monitor to do this, because taking your pulse manually is tricky while you’re exercising. (Stopping suddenly to take it isn’t a good idea if you’re working hard, because you should always cool down gradually.)
Once you know what your heart rate was while you were exercising, you can work out your exercise intensity. First, you need to work out your maximum possible heart rate. To do this, subtract your age from 220.
For example, if you are 40 your maximum heart rate will be 220 – 40 = 180.
Now you need to work out what the heart rate you recorded is as a percentage of your maximum.
For example, if you recorded a heart rate of 130bpm
Exercise heart rate as a % of maximum = 130/180 x 100% = 72%
This falls just inside the category of vigorous exercise:
- Heart rates 50-70% of maximum are moderate intensity exercise
- Heart rates 70-85% of maximum are vigorous exercise
- Above 85% is extremely high intensity. You should only work out at this level if you are already very fit
Combining moderate and vigorous physical activity
As stated above, the guidelines are 150 minutes of moderate or 75 minutes of vigorous activity. However, it’s unlikely that anyone is going to do 75 minutes of vigorous activity and no moderate activity at all. So as well as the minimum amounts for each, we need minimum amounts for combinations of the two.
The first thing to do is to work out how many minutes of general moderate activity you currently do. Maybe you do housework, gardening, walk the dog or walk to the bus stop for example. Then you can decide whether you want to do more moderate activity, add some vigorous activity, or do a bit of both. The table below shows how to combine minutes of moderate and vigorous activity to make up the total minutes needed for good health.
Safety note for vigorous physical activity
With vigorous exercise you need to warm up and cool down. It’s important to spend a few minutes warming up to prepare the joints and muscles for the vigorous movements to come. Taking a few minutes to cool down is important too, because stopping vigorous exercise suddenly can cause what is known as blood pooling. The muscles play a key role in returning blood to the heart and if they stop working suddenly, blood may be pumped away from the heart faster than it comes back. This can cause dizziness or even fainting.
So, if you are going to do a 15 minute exercise session, you will need to allow at least 5 minutes of this for warm up and cool down. However, these 5 minutes will count as moderate exercise.
It’s also important to be in good health generally. If you have any medical conditions, exercise may be beneficial, but strenuous exercise may not be appropriate. If in doubt, you should check with your GP first.
What counts as vigorous exercise?
The sort of activities you need to be doing for aerobic fitness are ones which increase your heart rate, breathing rate and body temperature. However, they need to be at a level that you can keep up for the whole workout. Examples of suitable activities are:
- Fast walking
- Rope skipping
- Step aerobics
- Dance based workouts
Strength training is important too
There’s far more information and advice available on aerobic exercise than strength training. This is because keeping our hearts and circulatory system healthy has a greater direct impact on health than strength training. Arguably it is better for weight control too, although this continues to be debated. It’s also true that cardio training will to some extent benefit bones and muscles, whereas strength training has limited benefits for cardio fitness. However, ideally we should combine our minutes of aerobic activity with a couple of strength training sessions a week.
The minimum recommendation from the ACSM for adults 18-64 years is:
2 x strength training sessions a week, to include 8-12 reps for each of the major muscle groups
This means that you need to do exercises for each of these areas of the body, with a resistance that tires you after 8-12 reps:
- Front of thighs
- Back of thighs
What to use as resistance
Depending on your strength levels, some exercises may be challenging enough without added resistance. For example, press ups, triceps dip, squats, lunges, calf raises and curl ups will tire some people within 8-12 reps.
Gyms have plenty of choice for resistance training. You can use machines, dumbbells, barbells, kettlebells, medicine balls, suspension straps or loaded resistance equipment such as sandbags and VIPRs.
At home, unless you have a home gym, you’ll want a few pieces of equipment that are versatile and easy to store. Any of the following are good for home workouts:
Resistance bands and tubes. Tubes work best for upper body and bands for lower body. Look for sets of tubes with a door anchor – this makes them much more versatile.
Suspension straps are also a good home choice, because they use your body weight. You only need one set of straps and then how hard you work depends on how you position your body.
Kettlebells and medicine balls are versatile and not too big and bulky, but you do need a selection of weights to allow for different strength levels in the various muscle groups.
Another option is to use a Swiss ball for a challenging strength workout. It obviously isn’t as easily stored, but you can work all your main muscle groups with this one piece of equipment and everything you do works your core.