How Much Is Enough? Exercise and the Healthy Heart
|Associate Director, Amy Rauworth|
To decrease your risks for heart disease, learn more about determining the amount and intensity of your cardiovascular exercise in this month's F.I.T.T. column.
How much is enough when it comes to physical activity? The Surgeon General's Report suggests 30 minutes of moderate-intensity physical activity on all or most days of the week. According to the new MyPyramid developed by the United States Department of Agriculture, daily recommendations are:
- to prevent chronic disease, 30 minutes of moderate-to vigorous-intensity exercise
- to maintain weight, 60 minutes of moderate- to vigorous-intensity exercise while not exceeding caloric intake, and
- to maintain weight loss, 60 to 90 minutes of moderate- to vigorous-intensity exercise while not exceeding caloric intake.
Just reading all these recommendations can make you tired and discouraged! And what is missing from these recommendations? People with disabilities! For example, there is not conclusive evidence on whether 30 minutes of cardiovascular exercise per day will increase the chance of overuse injuries in individuals who utilize wheelchairs for mobility. Until the research in this area is developed, there are a few general guidelines for increasing physical activity and improving cardiovascular fitness.
Fortunately, an updated set of guidelines that DO include people with disabilities has been published. The 2008 Physical Activity Guidelines for Americans provides science-based guidance to help individuals with disabilities aged 6 and older improve their health through appropriate physical activity. These guidelines serve as a new and vital resource that will help people with disabilities understand the types and amounts of physical activity that can generate substantial health benefits for all.
When beginning an exercise program, always start out slowly and increase gradually. For some individuals, intermittent exercise may be the best choice if prolonged exercise is not sustainable. Your body does not know the difference between three 10-minute bouts of moderate-intensity physical activity or 30 minutes of continuous moderate-intensity exercise. The key here is maintaining the intensity level during all workouts. A good way to judge exercise intensity is by calculating your target heart rate. Please note that this method is not appropriate for some individuals, such as persons using beta blockers, individuals with a spinal cord injury at or above T6, persons who have autonomic dysfunction, or any person with a disability with an unstable health status. Target heart rate can be calculated by using the Karvonen formula. To use this formula, you must first determine your resting heart rate. Before you get out of bed in the morning, take your pulse by gently placing your middle and index finger on your wrist or neck. Begin counting with zero and count your pulse for 10 seconds, then multiply by 6. Insert your resting heart rate into the formula below:
- (220) - (your age) = Maximum Heart Rate
- (MaxHR) - (resting heart rate) = Heart Rate Reserve
- (HRR) x (50% to 70%) = training range
- (training range %) + (resting heart rate) = (your target training zone)
If you prefer not to do a lot of mathematical calculations, you can refer to the Borg Rate of Perceived Exertion Scale. This scale is appropriate for all individuals with disabilities and subjectively allows each person to determine the level of intensity. The suggested level of RPE is between 11 and 13 on the 6 to 20 scale.
|Rate of Perceived Exertion
(Borg RPE 6-20 Scale)
|7||Very, Very Light|
|19||Very, Very Hard|
|20||Extremely, Extremely Difficult|
A final option to determine intensity is the talk test. You should be able to carry on a conversation during your workout. If you are breathless and cannot talk, you should decrease the intensity to a more comfortable level.
Get the most out of each minute of physical activity by determining the appropriate intensity level for you! If you have any questions about determining intensity, please feel free to contact me at firstname.lastname@example.org.