Q: I work out three times a week for 45 minutes each. Is it better to do my aerobic workout for two of the three sessions, and for the third do all my weightlifting? Or is it better to spend 30 minutes each time on aerobic exercise and 15 minutes each session on weightlifting.
– Jan McKenzie, Windsor
A: Without knowing your goals (dropping body fat? handling stress?) or physical situation (arthritis? osteoporosis?), I can’t give a definitive answer. Let’s look at what each of these activities provides in health benefits, and then you can make a well-informed decision.
Aerobic activity, along with healthy eating habits, is the key to weight control. For an activity to be “aerobic,” the exercise must elevate your heart rate to a point that is 50-80 percent above your resting heart rate, generally known as your target heart range. (Take your pulse first thing in the morning to determine your resting heart rate.) This range is very simplistically calculated by taking 220 (the maximum total beats per minute for women – 226 for men) minus your age. Since the heart is a muscle, it increases in strength when exercised because it must work harder to get oxygen to the muscles. As the heart gets stronger, it becomes more efficient at this task.
According to the University of Michigan Health System, any activity sustained for more than three minutes is considered aerobic. Aerobic exercise should be the main focus of most exercise programs because it decreases blood pressure, decreases resting heart rate (which reduces stress to the heart), increases the HDL (good) cholesterol, increases the efficiency of the heart and lungs and burns calories. A consistent and challenging aerobic program also will change body composition by increasing lean muscle and reducing fat, reducing the risk of stroke, diabetes and other lifestyle diseases, and elevating the mood, allowing for better coping abilities when you’re under emotional stress.
Aerobic activity uses both glucose and fat as a fuel source; anaerobic (“without oxygen”) activities such as weightlifting primarily use glycogen (stored in the muscles) to fuel the action. Weightlifting helps maintain and build bone health and increases general strength. Strong muscles improve the ability to function in daily living, including performing tasks like housework and gardening to carrying groceries and moving furniture. It is often forgotten that weight training can improve flexibility and decrease joint pain and is strongly encouraged for those suffering from arthritis, MS, fibromyalgia and other diseases.
While we may love a comfortable routine, the body loves change. Keep track of workouts week to week and change the intensity of your cardiovascular and strength activities. Add hills and sprints to your aerobic sessions and change the volume of the weights lifted, using heavier weights with fewer repetitions one week and lighter weights with more reps the next.
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