Heart Rate Zone

For many people, simply going for a walk or run is a function of their typical fitness week. To be more effective during your fitness time, consider the benefits of understanding more about your heart rate and the positive effect of having it in the right zone, to fast track your objectives.

At Plus Fitness we have many ways to establish the ideal heart rate training zone for you, from using our modern fitness equipment to working with a personal trainer consider what works best for you. Also the use of heart rate monitoring via watches, phone aps and Fitbit style of products are popular among our members.

Understanding exercising at a targeted heart rate was first calculated as being 220 – age = predicted ‘Heart Rate maximum’. This calculation has been shown in research to have a standard error of +/- 11bpm and was never developed with the intended use of HRmax prediction.

So training at intensities significantly above or below is optimum based on your goal.

Heart rate is a useful way of monitoring metabolic stress on the body as it has a linear relationship to oxygen consumption (VO2). As oxygen is required for aerobic metabolism to occur and this is the preferred means of generating energy in the human body, as energy demand increases so does oxygen demand and therefore heart rate. There are instances where heart rate is not an effective means of monitoring intensity, such as at near maximal intensities where anaerobic energy systems make a greater contribution to energy supply than the aerobic system. Certain medications, typically those prescribed for heart disease such as beta blockers, ACE or calcium channel inhibitors will truncate the heart rate response, meaning that a person’s heart rate will not increase above around 120 beats per minute (bpm) irrespective of exercise intensity. This does not mean that heart rate should not be monitored, but rather should occur in conjunction with other means of intensity monitoring.

1. Start by estimating maximum heart rate

The most accurate general HR max prediction equation according to a literature review by Robergs is that of Inbar:3

Heart Rate Max = 205.8 – (0.695 x age)

So for a 41 year old male this is calculated by 205.8 – (0.695 x 41 =28.495) = 177 beats per minute predicted maximum heart rate zone.

  1. Determine your zone

Based on the calculation above health professional, athletes and now you can determine your most effective zone by calculating a % of the maximum heart rate.

The calculation then looks like this – Max HR x by % = preferred training zone

Ie 50% of maximum for our 41 year old male is calculated by 177 beats per minute x 50% = 88 beats per minute.

3. Adding your training zone to your training

Understanding that there is are many variable and a huge range in fitness levels and age, this process helps to determine what will be work best for you.

  • 50-60%: There is little evidence for an improvement in fitness or performance; however, this level of intensity may be well suited to a person new to fitness or an introduction to becoming more active. Activity at this level, and below, is effective for improving health, reducing all-cause morbidity and the risk of developing many non-communicable diseases.
  • 60-70%: Training will start to establish adaptations associated with greater use of fatty acid oxidation as an energy supply, allow higher volumes of training to be performed without overtraining and prepare the musculoskeletal system for the higher intensity work to come.
  • 70-80%: Increased glycogen storage potential and efficiency of using this substrate aerobically. Training in this zone will lead to greater adaptation of the heart, lung and blood vessels than the lower-intensity sessions and, therefore, will have a greater influence on VO2max than lower-intensity training for most individuals.
  • 80-90%: Lactate threshold will be breached. Continued benefits to VO2max occur at these intensities for most individuals but the more significant changes for performance are gained from interval training at intensities above the lactate threshold, forcing their body to become more efficient at using anaerobic glycolysis to produce energy and at buffering acidosis in blood and muscles to prevent fatigue. Training methods such as high-intensity intervals and Fartlek have been shown to improve performance.
  • 90-100%: Is often claimed to lead exclusively to anaerobic energy system adaptations, particularly the phosphocreatine (PCr) system. While it is true that maximal or near maximal training is the most efficient means to improve maximal performance in events predominantly using this energy system, evidence already cited in this article identifies that, for some highly trained athletes, exercising in this intensity range is necessary to elicit any further changes in VO2max.

Although it can be useful to think of heart rate zones as gears in terms of the energy systems that are predominantly trained at each intensity range, it is important to be aware of the wide inter-individual variation and use additional means of monitoring and tracking intensity. Variation in resting and exercising heart rate response between individuals occurs for many reasons, primarily determined by an individual’s genetics and lifestyle choices. Our physiology and anatomy varies and even two people of similar size, gender and training background may have heart rates that respond very differently to exercise due to differences in heart function, blood vessel size, shape and elasticity, the levels of circulating hormones or neurotransmitter levels and many other reasons we can’t measure on the gym floor.

 

The difference between men and women

 

The formula for peak exercise heart rate that doctors have used for decades in tests to diagnose heart conditions may be flawed because it does not account for differences between men and women, according to research to be presented at the American College of Cardiology’s 63rd Annual Scientific Session.

The simple formula of “220 minus age” has been widely used to calculate the maximum number of heart beats per minute a person can achieve. Many people use it to derive their target heart rate during a workout. Doctors use it to determine how hard a patient should exercise during a common diagnostic test known as the exercise stress test.

After analyzing more than 25,000 stress tests, the researchers found significant differences between men and women and developed an updated formula to reflect those nuances.

“The standard that’s currently in use is somewhat outdated,” said Thomas Allison, M.D., cardiologist and director of stress testing at Mayo Clinic, and senior author of the study. “We want to make sure that when people do the stress test, they have an accurate expectation of what a normal peak heart rate is. Every so often, you need to recalibrate what’s considered normal.”

The new formula can help people better optimize their workouts and also improve the accuracy of test results. Stress tests, which are commonly used to help diagnose conditions such as coronary heart disease, heart valve disease and heart failure, require patients to exercise near their top capacity while technicians monitor the patient’s cardiac performance.

The researchers drew data from 25,000 patients who took stress tests at Mayo Clinic between 1993 and 2006. The sample included men and women 40 to 89 years of age who had no history of cardiovascular disease.

The study reveals that although everybody’s peak heart rate declines with age, the decline is more gradual in women. As a result, the previous formula overestimates the peak heart rate younger women can achieve and underestimates the peak heart rate of older women.

Women in the age range of 40 to 89 years should expect their maximum heart rate to be 200 minus 67 percent of their age. In men, the formula is 216 minus 93 percent of their age. For women younger than 40, the relationship of heart rate to age may be different, as an insufficient number of tests on women younger than 40 were available to provide reliable results.

The study also showed that younger men have a lower resting heart rate and higher peak heart rate than women and that men’s heart rates rise more dramatically during exercise and return to normal more quickly after stopping. The study did not investigate the physiological reasons behind the differences, although the researchers suggest hormones, especially testosterone, may play a role.

The previous formula was based on a study researchers now recognize as having serious limitations. For example, it included few women, a weakness common among older studies.

“It’s logical that an equation developed 40 years ago based on a group that was predominantly men might not be accurate when applied to women today,” Allison said. “But sometimes things just get stuck.”

Changes since the 1970s in terms of average body weight, fitness levels and attitudes toward exercise — particularly among women — justify a re-evaluation of peak heart rate norms, Allison said. Other recent studies have offered updates to the formula, but this study uses a larger sample size and is the first to include data from both men and women.

References

  1. Robergs RA and Landwehr R (2002), The surprising history of the “HRmax=220-age” equation, Journal of Exercise Physiology online, 5(2).
  2. Kolata G (24 April 2001), Maximum heart rate theory is challenged, New York Times.
  3. Inbar O, Oten A, Scheinowitz M, Rotstein A, Dlin R and Casaburi R (1994), Normal cardiopulmonary responses during incremental exercise in 20-70-yr-old men, Med Sci Sport Exerc., 26(5):538-46.
  4. Kravitz L, Robergs RA, Heyward VH, Wagner DR and Powers K (1997), Exercise mode and gender comparisons of energy expenditure at self-selected intensities, Med Sci Sports Exerc., 29(8):1,028-1,035.
  5. Tanaka H, Fukumoto S, Osaka Y, Ogawa S, Yamaguchi H and Miyamoto H (1991), Distinctive effects of three different modes of exercise on oxygen uptake, heart rate and blood lactate and pyruvate, Int J Sports Med., 12:433-38.
  6. Cassady S and Nielsen DH (1992), Cardiorespiratory responses of healthy subjects to calisthenics performed on land versus in water, Physical Therapy, 72(7):532-37.
  7. Edwards S and Foster C (2011), Be a better runner: A complete guide for the running enthusiast – improve your stride, avoid injuries, get the hottest equipment, train effectively for any race – and run further, faster, longer, Fair Winds Press, ISBN: 9781592334247.
  8. Swain DP and Franklin BA (2002), V? O2 reserve and the minimal intensity for improving cardiorespiratory fitness, Med Sci Sports Exerc., 34(1):152-7.
  9. Foster C et al. (2001), A new approach to monitoring exercise training, Journal of Strength and Conditioning Research, 15(1):109-115.
  10. Garber et al. (2011), ACSM Position stand, The quantity and quality of exercise for developing and maintaining cardiorespiratory,

Story Source:

The above story is based on materials provided by American College of Cardiology. Note: Materials may be edited for content and length.

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