Physical activity and exercise are not the same. Exercise is a structured activity designed to increase your heart rate or work your muscles for a specified period of time. Physical activity includes unstructured movement you do throughout the day. Being physically active encompasses things like housework, yard work, running errands, washing the car, and all of those unplanned activities that burn calories, whereas exercise is the HIIT routine you do or the weights you lift every other day. Here’s the question. If you’re doing lots of unstructured activity, do you really need exercise to stay healthy?
The Benefits of Being Physically Active
Research shows unstructured physical activity burns a significant number of calories. Based on research, a person can burn several hundred calories a day with non-structured movements, and a very active person can burn over a thousand calories. In fact, these movements count toward the recommendations of the Department of Health and Human Services – 150 minutes of moderate-intensity exercise weekly.
What’s clear is ALL physical activity provides health benefits because it’s non-sedentary behavior- and being sedentary is an independent risk factor for health problems. In fact, a study of older women found a linear relationship between the amount of time the participants spent sitting and mortality, even after the researchers controlled for other factors.
The bad news is studies show that sedentary behaviors make up about 55% of the activities the typical American does each day. This almost certainly plays a role in the growing epidemic of obesity. Another study showed obese men and women spend, on average, an additional 2 hours of sitting daily that thin people do not.
Sedentary behavior impacts metabolic health and the risk of type 2 diabetes as well. Movement enhances insulin sensitivity and improves the way your body handles lipids, thereby lowering the risk of metabolic syndrome and type 2 diabetes. In fact, watching television, another sedentary behavior is linked with higher systolic blood pressure, glucose, and triglycerides, as well as a larger waist circumference in women. So, simply being physically active improves metabolic health and reduces the risk of weight gain.
Physically Active vs. Structured Workouts
Do you even NEED structured exercise? Most experts will tell you that you do. For one, unstructured physical activity doesn’t improve cardiovascular fitness. The time you spend in unplanned exercise doesn’t increase your heart rate or challenge your cardiovascular system enough to cause it to adapt. Why is this important?
In one study, researchers measured the fitness level of more than 10,000 men and 3,000 women via a maximal treadmill test to determine their physical fitness level. What they found was mortality from heart disease and cancer was lower in proportion to how physically fit the participants were. Other studies also support the idea that cardiovascular fitness is an independent predictor of mortality.
In addition, cardiovascular exercise that increases your heart rate makes your heart a more efficient pump. Because your heart becomes more efficient, your heart rate slows and can still supply your tissues with oxygen. Cardiovascular exercise also lowers blood pressure, inflammation, and improves blood lipids. Again, casual, unstructured physical activity typically doesn’t offer these benefits. Plus, through structured cardiovascular exercise, you develop greater stamina and endurance. That comes in handy as you grow older.
What about Your Muscles and Bones?
As you know, you lose muscle mass and muscle strength after the age of 30. The only sure-fire way to slow that process is to strength train. You may be highly active throughout your busy day, but unless you train with weights or resistance bands, your muscles aren’t forced to adapt. This means that, over time, you will lose muscle at a faster rate than someone who DOES resistance train.
Why should you care about losing muscle? Muscle is what maximizes your resting metabolic rate – for weight control. Plus, having muscle size, strength and power helps you stay functional as you age. Weight training also improves your balance and helps you avoid falling and fracturing a hip.
Finally, you have to worry about your risk of osteoporosis. According to the National Osteoporosis Foundation, one out of two women will break a bone due to osteoporosis during a lifetime. High-intensity weight training and high-impact exercise help prevent bone loss and osteoporosis. Being more active throughout your day doesn’t typically stress your bones enough to force them to adapt and lay down new bone tissue. Therefore, you’re not getting the protection against osteoporosis that your bones so badly need.
One question is whether you compensate for structured physical exercise by being less physically active the rest of the day. Remember, your body tries to maintain homeostasis. If you expend energy doing a tough workout, your brain might subtly tell you to take it easy the rest of the day. Without being consciously aware, you scale back your extraneous movements and fidgeting, thereby burning fewer calories. There is evidence that this happens and it’s likely one reason exercise doesn’t always lead to weight loss. Plus, some people eat more when they work out. That’s why you have to keep your guard up even if you do regular workouts.
The Bottom Line
Ultimately, being physically active and structured exercise are important for health and fitness. Though unstructured physical activity lowers your risk of health problems and mortality, it doesn’t improve your fitness level or help you retain muscle strength and mass. It also has little impact on your risk of osteoporosis. If your goal is to be as fit and healthy as you can be, do a structured workout, cardiovascular and strength, but make sure you’re not sitting for the rest of the day either. The good news? If you do structured workouts, you’ll have the stamina you need to move more and get more out of life.
References:
Medscape.com. “A 2-Year Follow-Up of a Lifestyle Physical Activity Versus a Structured Exercise Intervention in Older Adults”
Am J Prev Med. 2014 Feb;46(2):122-35. doi: 10.1016/j.amepre.2013.10.021.
Med Sci Sports Exerc. 2008 Apr;40(4):639-45. doi: 10.1249/MSS.0b013e3181607421.
JAMA. 1989 Nov 3;262(17):2395-401.
N Engl J Med 1993; 328:533-537February 25, 1993DOI: 10.1056/NEJM199302253280803.
National Osteoporosis Foundation. “What is Osteoporosis and What Causes It?”
Med Sci Sports Exerc. 2011 Apr;43(4):624-31. doi: 10.1249/MSS.0b013e3181f7a0cb.
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