2000 Conference Proceedings
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THE CONVERGENCE OF EXERCISE, DIABETES AND HEART RATE
Authors: Cathy Mullooly, M.S.. C.D.E., Director Exercise
Physiology Joslin Clinic Pam Fernandas, Elite athlete.
The Benefits of Physical Activity
The American public is flooded with information on how physical
activity impacts health and wellness. Scientific studies show
that dozens of medical conditions are substantially improved and
in some cases prevented by participation in a fitness program.1
Medical as well as health and fitness professionals are actively
promoting physical activity as a means to reduce the risk of
developing chronic or debilitating diseases and maintaining
health. Even with this wealth of information, more than 60
percent of adults do not participate in regular physical
activity. Twenty-five percent of all adults admit that they are
not active at all. These American’s are more likely to be
older in age, female, less educated and make a lower
People with disabilities are also less likely to engage in
regular moderate physical activity than people without
disabilities. Yet, the argument can be made that they have even
more to gain from participating in some form of physical
activity. Participation in physical activity can promote health
and help prevent the progression of many conditions. Exercise can
improve stamina, increase muscle strength, bone density, and
reduce the symptoms of anxiety and depression that are often
present with chronic diseases and disabilities. Overall, physical
activity can help to improve mood and promotes feelings of
general well being while living with a disability. A disability
should not be an excuse to be sedentary. In fact, the lack of
physical activity may shorten a life.
Improving A Chronic Disease Through Exercise:
While there are many chronic diseases and disabilities that
inhibit participation in physical activity, the content of this
paper will focus on those associated with Diabetes Mellitus.
Diabetes devastating effects have long been recognized and are
well-documented 3,4. In 1996, 16 million Americans were estimated
to have diabetes. This number is expected to increase in the next
century. Diabetes is currently listed as the sixth leading cause
of death by disease in the United States. The true devastation of
the disease comes in its many complications. Cardiovascular
disease (CD) has the largest impact on the morbidity and
mortality of individuals suffering from diabetes. CD is 2 to 4
times more common in people with diabetes. It is present in 55 -
75% of diabetes related deaths. Other cardiac risk factors such
as hypertension (present in 60 - 65%) and lipid abnormalities
(present in up to 44%) are also common. Diabetes is also the
leading cause of blindness, cataracts, end-stage renal disease
and lower extremity amputations. Diabetes care in the USA alone
is estimated at $92 billion annually.
While these figures are discouraging, many of these
complications are known to be associated with long-standing
hyperglycemia. A number of recognized studies have shown that any
improvement in diabetes control (changes in the glycohemoglobin
A1c) dramatically reduces diabetes complications. 5,6,7 Also,
many people with diabetes are living active lives without any
restrictions due to the disease. This is the direct result of
regular exercise. In fact, a respectable number of diabetic
patients are elite professional athletes. The exact role that
exercise plays in preventing long-term complications has been
difficult to research. However, there are a significant number of
patients who lead a very active life reducing the severity and
eliminating the complications commonly associated with
The therapeutic use of exercise to control diabetes is not new.
It was prescribed as early as 600 BC by the Indian physician,
Sushruta, and was widely recommended by physicians of the 18th
century. In the early 1900’s, the impact that a single
exercise session has on blood glucose levels was first measured.
8,9 Since then, the long-term impact of exercise has also been
investigated. Studies have proven that HbA1C levels improve when
regular exercise is performed 10,11,12 and that some factors
involved in diabetic complications can be positively impacted.13
Monitoring the Intensity Level of an Exercise
Many professional organizations (i.e., American College of
Sports Medicine, American Heart Association, American Diabetes
Association, American Association of Cardiovascular and Pulmonary
Rehabilitation) have published clinical guidelines using heart
rate for prescribing a safe and appropriate exercise program.
Athletes regularly monitor heart rate to achieve maximum training
effectiveness, avoid injury, and ultimately improve performance.
Heart rate provides an indirect measurement of how much oxygen
the body is consuming for the production of energy, known as
oxygen uptake or VO2. Heart rate ranges are usually calculated
from a measured or estimated VO2MAX (maximal oxygen uptake).
Exercising within a certain heart rate range provides the most
beneficial effects. Ranges vary depending on an individuals goals
and limitations. By setting ranges appropriately, weight loss,
increased cardiovascular fitness, combating depression, improved
insulin resistance (possibly preventing diabetes), improved
athletic performance and lipid levels, and hypertension, all can
be positively effected.
Diabetes Complications and Exercise for Diabetes
While exercise is accepted as an important component in diabetes
control, the presence of diabetes complications requires certain
precautions. Because of the prevalence of cardiac disease in the
diabetic population, heart rate should be closely monitored. In a
supervised session, trained clinical exercise physiologists can
measure the heart rate by a variety of means and then set the
exercise workload accordingly. Patients exercising on their own
may not be able to do so. For example, the presence of diabetic
neuropathy inhibits pulse taking because of the loss of the
feeling at the fingertips. In these situations an important tool
is a heart rate monitor. One such device we have found
particularly useful is the HEARTalker™ heart rate monitor
because of its easy to understand verbal feedback.
The heart rate also becomes an important measure in the presence
of retinopathy (eye disease) and nephropathy (kidney disease). At
certain stages in both of these disease processes, blood pressure
changes need to be closely guarded. Any sudden or extreme changes
in this biological parameter is thought to exacerbate these
conditions which may then lead to vision loss or kidney damage.
By measuring the linear response of heart rate to blood pressure
changes during exercise, a maximum heart rate level during
exercise can be prescribed where the blood pressure response is
acceptable. Constant feedback is necessary throughout each
workout to insure these parameters are not exceeded.
Diabetic with vision loss would also find it impossible to
palpitate for a pulse because of the need to use a timepiece to
count seconds. In these instance, a HEARTalker talking heart rate
monitor provides the heart rate feedback required.
Athletes at all levels of experience acknowledge that monitoring
heart rate is a help in optimizing athletic performance. Those
athletes hindered by a disease such as diabetes should not be
prevented from reaching their peak performance because modern
technology is unavailable to them. Again, the HEARTalker monitors
fill this void very well so even those suffering from severe
complications of diabetes can receive the benefits of heart rate
Real Life Experiences of an Elite Athlete
One such athlete is Pam Fernandes. Pam is blind, she also
happens to be an elite athlete, and a five-time National Champion
for the United States Association of Blind Athletes (USABA)
cycling team. Pam earned the first USABA International medal in
cycling by capturing the silver at the World Championships in
Belgium. At the Atlanta Paralympic Games Pam won a bronze in the
one Kilometer Time Trial. Pam lost her sight 17 years ago as a
result of complication from type I diabetes. She is also a kidney
transplant recipient. For the past 17 years Pam has dedicated
herself to maintaining an active life style, remaining
independent, staying fit, and competing as a world class athlete.
Pam has not allowed blindness to stop her. She constantly looks
for ways to help her achieve her goals in life.
Health and fitness have always been important to her. As a
sighted youngster she was involved in many team sports, but with
the onset of her blindness and subsequent kidney failure at the
age of 21 she could no longer exercise in the same manner as
before. After the kidney transplant in 1987 she yearned to become
physically active again, both for health reasons and to lose
weight gained while recuperating and from the anti-rejection
medication. Joining a local gym and enthusiastically throwing
herself into aerobic exercise and weight training, Pam gained
strength, lost weight and increased her cardiovascular fitness.
The positive effects exercise had on her physically and mentally,
challenged her to set goals and strive to work harder to meet
In 1993 Pam discovered tandem cycling when attending a racing
camp held at the U.S Olympic Training Center in Colorado Springs.
The camp accelerated her learning curve for cycling and ignited a
passion for the sport. She learned new training methods and about
the body’s physiology, diet, and competitive racing. She
was also exposed to heart rate monitoring for the first
Unfortunately, existing heart rate monitors were not very
friendly to someone who is blind. The available wireless monitors
used a digital watch to provide heart rate feedback. A beeping
sound alerted the user when exercising out of the prescribed
target heart rate zone. This was difficult for Pam to use, and
required that she depend on others to set target zones than help
her interpret the monitor’s feedback. She was determined to
find a way to get the information she needed in order to train
like every other elite athlete.
Old Problem Solved by New Technology In 1998 Pam found
the solution to her heart rate training dilemma. A friend
suggested she try a new heart rate monitor, the HEARTalker
Personal Trainer. With all the heart rate feedback delivered
verbally, the HEARTalker was just the tool Pam had been seeking
to help her train independently. The HEARTalker monitor performed
well for her and it was not expensive. Many products produced
just for the disabled cost too much to be widely used. Like any
piece of new equipment Pam experimented with it, walking around
the house wearing it to get a feel for how it worked. To quote
Pam, "the monitor is so easy to use even a blind person can use
it". Training became more enjoyable because the feedback she was
getting helped her trainer more effectively and she again found
herself to be more self dependent in her workout
How Heart Rate Training Works The competitive athlete who
uses a heart rate monitor first must determine their maximum
heart rate (MHR). This value can be determined by a number of
ways. The most popular estimated method is to use the value 220
minus the person’s age. This method is appropriate average
individuals but is inadequate for the competitive athlete because
of their conditioning. For competitive athletes the VO2MAX
(maximal oxygen uptake) test is often used to determine MHR.
Other test methods are also available. Once the MHR value is
determined, an effective training program can be established.
Pam’s training included workouts at heart rates of 70%,
80% and 90% of her MHR, so heart rate monitoring has to be
accurate and reliable. On easy workout days her heart rate was
kept below 70% MHR. Certain workouts require Pam to keep her
heart rate at 140 BPM for one hour. Before HEARTalker this would
have been impossible to monitor. Needless to say, her coach is
excited about this new piece of training equipment.
For competitive athletes one of the biggest problems is over
training. Too frequently the athlete succumbs to the seduction
that "more is better". Combine this with a "type A" personality
and you have a recipe for disaster, put another way, the road to
certain injury. If the athlete is knowledgeable about how the
heart responds to training the intensity can be adjusted
appropriately. Heart rate trained athletes know that if the
resting heart rate is elevated something is wrong. Additional
warning signals include rapid increases in heart rate and slower
recovery to normal levels. These may be signals that the body has
not recovered from a previous workout, or an indication of other
more serious problems. Heart rate can be a reliable indicator as
to the overall health and fitness of the body. Regular use of a
heart rate monitor makes it possible for anyone to better
understand their body in order to pace themselves for a safer
more effective exercise program.
Heart Rate Monitoring for the Average Diabetes
The HEARTalkerÔ Personal Trainer heart rate monitor is not
just for the competitive athlete. The heart is the most important
muscle in every body, not just the body of athletes. When the
heart becomes more physically fit endurance is improved.
Exercising with a heart rate monitor helps anyone exercise at the
safest and most beneficial level based on age and fitness
Exercise benefits previously mentioned such as weight loss,
lower blood pressure, reduction of stress and depression can all
be realized sooner and with less strain when a heart rate monitor
helps manage the intensity of the exercise. Cardiovascular
benefits can help improve the quality of life many patients.
Perhaps the biggest benefit to diabetics is the positive effect
exercise has on lowering blood sugar which results in the need
for less insulin. Exercise as simple as a brisk walk for 30
minutes at 70% MHR can have a significant effect on blood sugar.
Careful monitoring of blood sugars is required to achieve best
results. Make exercise a daily part of life.
- Designed for Action.
ACSM’s Health & Fitness Journal, May/June 1999, Vo1 2,
No. 3, 30-37.
- U.S. Department of
Health and Human Services: Physical Activity and Health: "A
Report of the Surgeon General." Centers for Disease Control and
Prevention, National Center for Chronic Disease Prevention and
Health Promotion, Washington, DC, U.S. Govt. Printing Office,
- National Diabetes
Information Clearinghouse. Diabetes Statistics. NIH Publication
No. 96-3926. October, 1995.
- American Diabetes
Association. Diabetes 1996:Vital Statistics,1996.
- The Diabetes Control
and Complications Trial Research Group. The effect of intensive
treatment of diabetes on the development and progression of
long-term complications in insulin-dependent diabetes mellitus.
N. Engl. J. Med. 329:977-986, 1993.
- Ohkubo Y., H.
Kishikawa, E. Araki, et al. Intensive insulin therapy prevents
the progression of diabetic micro-vascular complications in
Japanese patients with non-insulin-dependent diabetes mellitus: a
randomized prospective 6-year study. Diabetes Res. Clin. Pract.
- UK Prospective Diabetes
Study Group. Intensive blood glucose control with sulfonylureas
or insulin compared with conventional treatment and risks of
complications in patients with type 2 diabetes (UKPDS 33)Lancet
- Lawrence R. D. The
effect of exercise on insulin action in diabetes. Brit. Med. J.
- Marble A. and R. M.
Smith. Exercise in diabetes mellitus. Arch. Intern. Med.
- Scheider S. H., L. F.
Amorosa, A. K. Khachadurian, and N. B. Ruderman. Studies on the
mechanism of improved glucose control during regular exercise in
type II diabetes. Diabetologia 26:355-60, 1984.
- Scheider S. H., A. K.
Khachadurian, L. F. Amorosa, L. Clemow and N. B. Ruderman.
Ten-year experience with an exercise-based outpatient lifestyle
modification program in the treatment of diabetes mellitus.
Diabetes Care 15(Suppl. 4):1800-10, 1992.
- Stratton R., D. Wilson,
R. K. Endres, and D. E. Goldstein. Improved glycemic control
after supervised 8-wk exercise program in insulin-dependent
diabetic adolescents. Diabetes Care 10:589-93, 1987.
- Veves A, Saouaf R,
Donaghue VM, Mullooly CA, Kistler JA, Giurini JM, Horton ES,
Fielding RA. Aerobic exercise capacity remains normal despite
impaired endothelial function in the micro- and macrocirculation
of physically active IDDM patients. Diabetes 46: 1846-1852,
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