How To (Properly) Calculate Your Target Heart Rate Zone

Monitoring our heart rate during exercise is an excellent way to determine and quantify the intensity of our workout. But what intensity should we be working out at and what is the best way to calculate this? The traditional method of calculating your target heart rate (Percentage of Predicted Maximum Heart Rate) factors in only your age (Predicted Max HR = 220 - Age). For example, world-class ultramarathoner Scott Jurek is 46 years old and therefore has a predicted maximum heart rate of 174 beats per minute (bpm). While using this traditional method, most recommend a target heart rate zone (the zone you want your heart rate in during exercise) to fall between 50-85% of your maximum heart rate. For Scott Jurek, we find his target heart rate zone to be roughly 87-148 bpm. The benefit of this method lies in the simplicity of the calculation. However, there are shortfalls of utilizing this method to calculate target heart rate zones. First, the range of this target heart rate zone is much too large and subsequently not very prescriptive. Second, the low end of this target heart rate zone may not be attainable during exercise, especially in older adults with higher resting heart rates. For example, the predicted maximum heart rate for a 75 year old woman is 145 bpm. Let’s assume this individual has a resting heart rate of 75, which is fairly typical. Utilizing the traditional method results in a calculated target heart rate zone of 73-124 bpm. As you can see, her resting heart rate is higher than the low end of her target heart rate zone for exercise. Therefore, the percentage maximum heart rate method of calculating her target heart rate zone would say she is exercising at rest, which is nonsensical. In other words, the traditional method often prescribes heart rates that are too low when working out at lower intensities, especially in older adults. Third, the traditional method fails to factor in your level of fitness, thus overly simplifying exercise prescription for a variable population. Since the traditional method of calculating your target heart rate fails to factor in your resting heart rate, it will prescribe the same target heart rate zone for Scott Jurek as an age-matched couch potato who smokes two packs per day. You see, as you become more fit, your resting heart rate will decrease as your heart becomes stronger and subsequently more efficient at pumping blood to the rest of your body. A highly trained athlete may have a resting heart rate of 48 bpm while the sedentary smoker may have a resting heart rate of 88 bpm. If they are both 40 years old, the traditional method of calculating target heart rate would recommend exercising between 90 and 153 bpm for both individuals. The traditional method therefore lacks this level of specificity.

So what is a better way to calculate your target heart rate zone? The answer is using the Karvonen method, otherwise known as the Heart Rate Reserve (HRR) method. The Karvonen method factors in both your age and resting heart rate, allowing for a more precise and effective target heart rate zone. The low end of the target heart rate zone tends to be at a higher heart rate than the traditional method of calculating target heart rate zones, while the predicted maximum heart rate is still the same. Those with a higher resting heart rate will see a higher number at the low end of the target heart rate zone as compared to those with a lower resting heart rate, to account for variability in the baseline levels of cardiovascular fitness within the population. Click on the link below to calculate your target heart rate zone using the Karvonen method:

TARGET HEART RATE CALCULATOR

Once calculated, it is recommended that you use this target heart rate zone to monitor your intensity during your workouts, in order to ensure that you are exercising at an intensity high enough to provide a cardiovascular benefit. This will help you get the most out of your exercise routine moving forward.

To find more information on heart rate or how to find your pulse, CLICK HERE.

-Grant Hennington, DPT

Osteoarthritis: Misbeliefs About a Common Joint Condition

The term arthritis is defined as acute or chronic joint inflammation. Although there are many types of arthritis, including rheumatoid arthritis and psoriatic arthritis, osteoarthritis in the most common form. Osteoarthritis affects millions of active and sedentary adults worldwide.

Osteoarthritis involves changes in a joint’s cartilage and bone that may lead to joint pain and swelling. Osteoarthritis typically affects the joints of the knees, hips, lower back, neck, and small joints of fingers, thumb, and big toe. Pain associated with osteoarthritis is typically described as an aching or burning joint pain that gets worse with activity. The affected joint will often feel stiff and painful in the morning for about an hour and then feel sore again towards the end of the day.     

WHAT CAUSES ARTHRITIS?

A healthy joint will have solid layers of articular cartilage that allow smooth movement and force absorption between bones. These layers of cartilage are maintained by cells called chondrocytes. In an arthritic joint there is a shift in the chondrocyte activity leading to decreased cartilage production and impaired cartilage maintenance.  

This change in chondrocyte activity causes an increase in immune cell activity which can result in inflammation in the joint, with subsequent pain. Altered chondrocyte activity may be due to age, inflammation, joint injury, mechanical load and obesity, and genetics.

COMMON MISBELIEFS ABOUT ARTHRITIS

“Exercise will damage my joints more by increasing the force between the bones.”

Decreasing or stopping regular exercise due to osteoarthritis can lead to reduced muscle strength around the joint, decreased flexibility, weight gain, and difficulty with normal daily activities. Strengthening and stretching the muscles around an arthritic joint can actually decrease the friction and load on the joint. Regular exercise can keep the muscles around the joint strong, decrease bone loss, and can help control joint swelling and pain. Movement of joints also promotes the production of synovial fluid, which acts as a lubricant to reduce joint friction. It is well documented in research literature that regular participation in an appropriate exercise program can increase joint motion and strength, increase aerobic capacity, and improve physical and psychological function in people with osteoarthritis. 

“Arthritis is degenerative, so my pain and function are only going to get worse as I age”

As we age, osteoarthritic changes may become more pronounced on imaging, including x-rays and MRI. However, your strength, function, and pain do not have to worsen just because a joint is becoming more arthritic. Many people get concerned when they are told their x-rays are positive for osteoarthritis or signs of degeneration. However, even though your joint may look a certain way on imaging it does not mean you will have pain or difficulty using that joint in daily and higher level activities.  

“I have arthritis in my knees so I should only be doing low impact activities, like swimming and biking” 

Low impact exercises like swimming, biking, and elliptical machines can be great aerobic activities for people with osteoarthritis, especially if they are beginning an exercise program or have limited mobility due to their osteoarthritis. However, these exercises should be part of a program that also incorporates mobility and strengthening exercises. A good exercise program involves finding the right type of exercises that allow you to keep moving without high levels of pain.  If swimming and biking help accomplish this, then it is perfectly fine to make these a staple of the program. However, if you have a goal to walk with less pain, walking eventually needs to be a part of your program, with graded progressions in time or distance when appropriate.

“Running causes arthritis and will ruin your knees in the long-term”

Many of the long-term studies on runners suggest that, as long as your knees are healthy to begin with, running does not increase the risk of developing arthritis, even if you run into middle age or beyond. In some studies, runners show less overall risk of developing arthritis compared to less active individuals. Other studies have even suggested that regular loading of cartilage with appropriate rest periods may help encourage cartilage cells to divide and improve cartilage health in the long-term.  

IN SUMMARY: KEEP MOVING, STAY STRONG, AND FIND THE RIGHT PROGRAM FOR YOU!

Osteoarthitis can be painful and lead to impaired mobility and activity. However, finding the right combination of activities, improving your strength and flexibility, and staying consistent over time can result in decreased pain and improved function.  Remember that you are not your x-ray and pain-free activity may be possible despite what the imaging shows.  It may take time and work, but the right aerobic, strength, and flexibility program can go a long way in combating osteoarthritis pain.

-Sean Tyler, DPT

Getting Back To The Basics For Health & Wellness

Raise your hand if you think you get enough exercise per week. Now raise your other hand if you think you get enough sleep per night. Are both your hands up? If yes, kudos to you, as statistically you are in the minority among adults in the United States. If no, where do you think you are lacking? According to the Centers for Disease Control and Prevention (CDC) adults need at least 150 minutes of moderate-intensity exercise per week and at least 7 hours of sleep per night. For those of you with both hands up, are you meeting these recommendations or do you need to put a hand down? The health benefits of regular physical activity are numerous and well documented, with exercise being linked with reduced risks of cardiovascular disease, diabetes, and several types of cancer. And we also know insufficient sleep has been linked with many chronic diseases, such as diabetes, heart disease, obesity and depression. Getting the picture? If you were to think of exercise and sleep as prescription drugs, they would be some of the most safe, effective, and affordable drugs in history, without the significant side effects of common pharmaceuticals. Exercise and sleep also appear to be equal opportunity interventions, as the health benefits apply to both men and women of all ages, races, and ethnicities, according to the CDC. Unfortunately, approximately one-half of adults in the United States do not get enough exercise per week and one-third of adults do not get enough sleep per night. This could partially explain why nearly two-thirds of adults in the United States are overweight or obese.

So why do we have such an inactive and sleep deprived population? Most of us could carve out 30 minutes per day for 5 days each week and tuck ourselves in 30-60 minutes earlier each night. So what’s the hold up? For one, starting to exercise regularly and sleep more requires behavior change, which can be difficult to initiate and stick with. Beginning an exercise program is often uncomfortable and unpleasant, especially if you are typically sedentary. The good news is there are several gentle forms of physical activity that fall in to the “moderate-intensity” category, according to the CDC:

• Walking

• Swimming

• Going for a bike ride

• Yoga

• Dancing

• Yard work

• Water aerobics

As you can see, there is no need to take up running or team sports if you want to get fit. It should also be noted that each form of exercise does not need to be performed all at once, as three separate bouts of walking for 10 minutes per day would count for 30 minutes and carries with it similar health benefits. An added perk is that regular physical activity has been linked with improved quality of sleep so you can be working on both aspects of health and wellness with one deed. What a deal!

So, if you find yourself not feeling well as of late, check in to see if you are meeting your basic physical activity and sleep recommendations first and foremost. If you are not, try to work up to it and see if it helps before turning to sophisticated and expensive tests, treatments, and/or procedures. If you are getting 150 minutes of exercise per week and sleeping 7+ hours per night, but are still not feeling well, then it may be appropriate to seek out an evaluation by a medical professional.

For more information regarding physical activity and sleep from the Centers for Disease Control and Prevention, click on the following links:

CDC Physical Activity Basics

CDC Basics About Sleep

-Grant Hennington, DPT