By Gabe Mirkin, M.D.
Your maximum heart rate is the fastest your heart can beat and still pump blood effectively through your body. As you age, your maximum heart rate drops. This means that your heart is weaker and more susceptible to damage, and you can’t exercise as fast over distance as you could when you were younger.
How fast you can run, cycle, ski or swim over distance is limited by the time that it takes to move oxygen into your muscles. Your heart pumps oxygen-rich blood to your muscles, so the faster your heart can beat, the more blood it can pump to your muscles and the faster you can move.
Exercise physiologists use your maximum heart rate to determine your level of fitness and guide the intensity of training. A recent study from Ball State University in Indiana shows that exercising as you age slows down the loss of maximum heart rate (Med Sci Sports Exerc, Jan, 2016;48(1):73-81). Keeping your maximum heart rate up means that your heart is stronger, which allows you to exercise faster and longer. Exercising as you age can also prolong your life and help prevent heart attacks, cancers, strokes, diabetes, being overweight and more.
Nearly 650 healthy men and women, ages 18-80, not taking any heart-rate-altering medications, completed two treadmill all-out efforts at least one year apart. The older participants had lower average maximum heart rates, but those who were most fit and had the highest values had the least drop in their maximum heart rates over the year, regardless of age.
Strong Legs Enable a Higher Maximum Heart Rate
The standard Maximum Heart Rate Formula (220 – Age) is based on averages and is not accurate. You can beat these averages if you exercise effectively. Your actual maximum heart rate depends more on the strength of your legs than it does on the strength of your heart.
When you contract your leg muscles, they squeeze against the blood vessels near them to pump blood from your leg veins toward your heart. When your leg muscles relax, your leg veins fill with blood. When you exercise, your leg muscles pump increased amounts of blood toward your heart. This increased volume of blood fills the heart, which causes your heart to beat faster and stronger. This is called the Bainbridge reflex. The stronger your legs are, the more blood they can pump back to your heart, which causes your heart to beat faster.
Wisely Using Maximum Heart Rate Formulae
Maximum heart rate formulae can be used to help you plan and monitor your exercise program, but they should not be interpreted as absolute limits or goals. If you want to train to become faster by increasing your maximum heart rate, you should follow a program based on “stress and recover.” To increase your maximum heart rate, you need to become short of breath at some time during your exercise. However, when you exercise at high intensity, you damage muscles and have to allow time for them to recover. If you don’t allow muscles to recover, you can become injured and can develop an overuse syndrome in which you are exhausted and won’t be able to exercise at all.
I believe that all healthy people should use some variation of a stress-and-recover exercise program, in which they damage their muscles by going a little harder and faster on one day, then feel soreness in their muscles and go much slower on the next day. When their muscles feel fresh again, they can take another intense workout.
For example, a runner may warm up by going slowly and then run a little faster for 50 strides, then slow down until he recovers his breath and his muscles feel fresh, and then alternate the faster and slower runs until his legs start to feel heavy or hurt. On the next day, his muscles should feel sore and he either takes the day off or runs very slowly. He should try to set up a program in which he goes faster on one day and much slower on the next.
- A hard day means getting short of breath and feeling some burning in your muscles.
- An easy day means that you do not become short of breath and should not feel muscle soreness as you continue to exercise. If your legs feel heavy after you warm up, take a day off from exercising.
- You don’t need to know your maximum heart rate.
- You don’t need to use a maximum heart rate formula to govern your training.
- You don’t need a heart rate monitor.
- All training should be governed by how you feel.
- Never train intensely when your muscles feel worse as you continue to exercise.
Caution: People who have narrowed arteries leading to the heart can suffer heart attacks when they exercise intensely. All vigorous exercisers must learn when to back off of training because not allowing enough time to recover from hard exercise can damage your heart muscle as well as your skeletal muscles. Check with your doctor before beginning an exercise program or making a sudden change in the intensity of your existing program.