Today’s post, How Much Exercise Is Enough, is in response to a question posed by one of the members of my Facebook community. (I’m always happy to answer your burning questions about midlife fitness and nutrition too; either here on the blog or over on Periscope, a new live-broadcasting app that I’m testing out Thursday mornings at 8:00 am PT. You can watch it live or in ‘re-runs’ for 24 hours post-broadcast. You can find me at @TamaraGrand).
I frequently share short short (20-30 minute) workouts with my social media followers.
They’re my own preferred way of working out and are the foundation of the types of workouts I create for my clients and online women’s fitness group.
Kathryn asked me about how these types of workouts fit within the government’s recommendation that healthy adults and older adults get 30 (and more recently 60) minutes of physical activity per day; essentially asking how much exercise is enough.
“So just curious – these 20 minute and under exercise work outs – how do they figure in with the 30 minute a day – or now they are saying an hour would be ideal – recommendation? I feel like one minute we’re told that a longer, more moderate work out (like walking) is better and then told that shorter bursts of intense activity are preferred. And just to clarify…the 150 minutes does NOT include strength training or yoga? Thanks, Tamara!”
Because this is a great, multi-part question, I’m going to break it down into three parts; how much, how intense and what types of activities count.
How much exercise is enough?
According to the American Council on Exercise, healthy adults and older adults should aim for 150 minutes of physical activity per week. This recommendation is based on studies showing that adults who don’t meet this level of activity are more likely to be overweight and at greater risk of heart disease, stroke and type two diabetes.
Ideally, those 150 weekly minutes will be broken down into five, 30-minute periods of exercise. Although 10-minute bouts of more intense effort (see below for a discussion of ‘intensity’), spread throughout the day may provide the same effects.
Recent studies suggest that exceeding 150 minutes per week has additional health benefits and that the new target should be closer to 300 minutes of physical activity per week (that’s where Kathryn’s comment about 300 minutes comes from; I love how informed my readers are!)
How intensely do I need to be working?
Kathryn’s question really revolves around the issue of intensity. How intense does an activity need to be to ‘count’?
ACE’s recommendations stipulate that those 150 minutes of physical activity need to ‘moderately intense’ to ‘vigorous’. But was do ‘moderately intense’ and ‘vigorous’ really mean?
The best yardstick for measuring intensity is heart rate. The higher your exercise heart rate, the harder you’re working and the higher the intensity of the workout. Not only do higher intensity workouts challenge your cardiovascular system more than lower intensity workouts (building a stronger heart and lungs is a key component of fitness), they also result in more calories burned, a key consideration if weight loss or weight loss maintenance are your primary goals.
A ‘moderately intense to vigorous’ workout will elevate your heart rate up to somewhere between 60 and 90% of maximum heart rate
MaxHR is most easily estimated by subtracting your age from 220; I’m 48, so my maxHR equals 220 – 48 or 172 beats per minute, resulting in a target exercise heart rate of somewhere between 103 and 155 beats per minute. You can also use the Karvonen formula if you know your resting heart rate; it’s a bit more accurate, especially for people who are already fairly fit.
What types of activities can I include?
Historically, the above recommendations were made specifically with regards to cardiovascular training, with additional weekly recommendations for strength training and flexibility training.
Hence any traditional cardiovascular-based activity will count towards the 150-minute weekly goal; running, cycling, swimming, rowing, cardio machines in the gym, skipping and calisthenics to name a few.
Walking may meet the criteria, especially if you walk quickly (like you’re trying to catch the bus at the corner) and your route has hills and other variable terrain.
However, many types of workouts incorporate multiple training elements. For example, while Bootcamp and CrossFit-style workouts typically focus primarily on strength training, because of the way they’re structured they also elicit a cardiovascular response. Heart rates remain elevated throughout the workout, simultaneously strengthening both muscles and the cardiovascular system.
Metabolic strength training, circuit-style weight lifting and power yoga may also ‘fill the bill’. As do those 20-30 minute workouts I share on YouTube, Facebook and here, on the blog.
Focus more on how intense the workout is than whether it’s a ‘cardio’, ‘strength’ or ‘flexibility’ workout when you decide whether to count it towards your weekly physical activity goals.
A few caveats
- Exercise intensity is individual. The amount of effort a sedentary, non-exerciser would have to expend to generate the appropriate heart rate effect will be different than that of a long-time, consistent exerciser. If you’re new to exercise, I strongly recommend that you get familiar with your heart rate!
- Recommendations are only guidelines. Newcomers to exercise shouldn’t feel compelled to immediately reach the 150-minute per week guideline. Start with a frequency, intensity and duration that challenges you, but that allows you to be successful. Build on to it as your strength and endurance increases. I might start a brand-new-to-exercise client with only three 15-minute bouts of exercise per week; woefully short of the government recommendations, but a do-able first step for that client.
- Just because you exercise intensely for 30 (or even 60) minutes a day, doesn’t mean you wouldn’t benefit from more movement. If you spend the rest of your day sitting at your desk or behind the wheel of your car, that 30 minutes of exercise may not be enough to keep weight gain, heart disease and diabetes at bay. Interspersing frequent bouts of low intensity, non-exercise activity throughout your day will elevate the effects of your workouts.
- Walking has many health benefits. For beginners to exercise, it’s often a workout on it’s own. For the rest of us, in particular, midlife, hormonally challenged women, it’s a great way to reduce stress (and the concomitant production of stress hormone which contributes to midlife weight gain). Think of it as a ‘bonus’. Meet your 30 minute heart-rate accelerating goal, then cool down and relax with a leisurely walk. Combine that with the company of a friend or loved one and you’ve done more than you can imagine for your health!
Here’s a sample of the short, but intense, whole-body, metabolic strength workouts that form the bread and butter of my own, personal fitness regime.
If you like it, please take a minute to share it with your friends (it’s super easy; just click on one of the social sharing buttons at the bottom of the post and presto, you’ve made a difference in somebody else’s life ).