Expert: Brandon Briggs, MS - 5/1/2008

Question
I am pretty lean and fit but am embarking on an intensive exercise program
after a stage I breast cancer surgery in order to reduce recurrence chances
due to high estrogen. I read that exercising "30+ miles a week" does just
that. But it's hard to calculate miles on my slideboard (I do 150 min a week
right now). Is time more important than miles when getting targeted fitness
benefits? How does one calculate these things? It seems to me that riding a
bike uphill for an hour is a lot better than moderate cycling for three hours!  

Answer
Hi Jenny,

This is a question I get a lot. However the answer depends on your fitness goal. Whether for general fitness or weight loss the general concept is the same. Exercising for mileage involves the speed at which you are exercising. Let me explain this in terms of walking. When walking 3 miles in on hour you are walking at 3 mph. If you increase you mileage to 3.5 miles in that same time duration you are waling 3.5 mph. Generally if you increase your intensity you will increase your heart rate in a lateral fashion. One you reach your target heart rate you need to exercise in that zone. The American College of Sports Medicine recommends that you get at least 30 min of exercise most days of the week. By most days they are implying 4-6 days a week. Break that down into minutes you have 120 - 180 min per week. My suggestion is exercise at a challenging intensity 4-5 days a week for 30 - 45 minutes. Challenging would be rating your exercise a 12-15 on the Borg Rating of Perceived Exertion scale. A rating of 13 is considered somewhat hard. If i can help you further please contact me. I can get more detailed after learning more information from you.

Brandon