Introduction
The function of the heart is to circulate blood around the body. The
heart comprises of four chambers:
- Right Atrium
- Left Atrium
- Right Ventricle
- Left Ventricle
Functionally the heart comprises of two pumps:
- The right atrium receives blood from from the the body (de-oxygenated
blood) and the right ventricle pumps it into the lungs for aeration
(removal of carbon dioxide and add oxygen).
- The left atrium receives the oxygenated blood from the lungs and the
left ventricle pumps it around the body.
Blood Pressure
The cardiac cycle (heart beat) consists of cardiac muscle contraction
(systole) and cardiac muscle relaxation (diastole).
Blood pressure represents the force (pressure) exerted by blood against
the arterial walls during a cardiac cycle. Systolic blood pressure, the
higher of the two pressure measurements, occurs during ventricular
contraction (systole) as the heart pumps blood into the aorta.
After systole, the ventricles relax (diastole), arterial pressure
declines and the heart refills with blood. The lowest pressure reached
during ventricular relaxation represents the diastolic blood pressure.
Normal systolic blood pressure in an adult varies between 110 and 140 mm
Hg, and diastolic pressure varies between 60 and 90 mm Hg.
Blood Pressure Classification
|
Systolic (mm
Hg) |
Diastolic (mm Hg) |
Classification |
| <130 |
<85 |
Normal |
| 130-139 |
85-89 |
High Normal |
| 140-159 |
90-99 |
Hypertension (stage 1) |
| 160-179 |
100-109 |
Moderate Hypertension (stage 2) |
| 180-209 |
110-119 |
Severe Hypertension (stage 3) |
| >209 |
>119 |
Very Severe
Hypertension (stage 4 |
|
Overview
Athletes who use a heart rate monitor as a training aid need to identify
their maximum heart rate in order to determine their appropriate
training zones.
Calculation of Maximum Heart Rate
The easiest and best known method to calculate your maximum heart rate
(MHR) is to use the formula 220-age. A paper by Londeree and Moeschberger
from the University of Missouri-Columbia indicates that the MHR varies
mostly with age, but the relationship is not a linear one. They suggest an
alternative formula of 206.3 - (0.711 * age). Similarly, Miller et al from
Indiana University propose the formula 217- (0.85 * age) as a suitable
formula to calculate MHR.
Londeree and Moeschberger also looked at other variables to see if they
had any effect on the MHR. They found that neither sex or race make any
difference but they did find that the MHR was effected by the activity and
levels of fitness.
Studies have shown that MHR on a treadmill is consistently 5-6 beats
higher than on a bicycle ergometer and 2-3 beats higher on a rowing
ergometer. Heart rates while swimming are significantly lower, around 14 bpm,
than for treadmill running. Elite endurance athletes and moderately trained
individuals will have a MHR 3 or 4 beats slower than a sedentary individual.
It was also found that well trained over 50s are likely to have a higher MHR
than that which is average for their age.
To determine your maximum heart rate you could use the following which
combines the Miller formula with the research from Londeree and Moeschberger.
- Use the Miller formula of MHR = 217 - (0.85 * age) to calculate MHR
- Use this MHR value for running training
- Subtract 3 beats for rowing training
- Subtract 5 beats for bicycle training
- Subtract 3 beats for elite athletes under 30
- Add 2 beats for 50 year old elite athletes
- Add 4 beats for 55+ year old elite athletes
% MHR and %VO2 Max
It is possible to estimate your exercise intensity as a percentage of
VO2 Max from your
training heart rate. David Swain (1994) and his US based research team using
statistical procedures examined the relationship between %MHR and %VO2 Max.
Their results led to the following regression equation :
- %MHR=0.64 * %VO2 Max + 37
The relationship has been shown to hold true across sex, age and
activity.
Associated Journals and Books
The following journals and books contain more information on this topic:
- Peak Performance - Issue 27, page 8
- Peak Performance - Issues 104 page 5,6, & 7
- Londeree and Moeschberger (1982) 'Effect of age and other factors on
HR max' - Research Quarterly for Exercise & Sport, 53(4), 297-304
- Swain et al (1994) 'Target HR for the development of CV fitness' -
Medicine & Science in Sports & Exercise, 26(1), 112-116
- Miller et al (1993) - 'Predicting max HR' - Medicine & Science in
Sports & Exercise, 25(9), 1077-1081
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Introduction
Fitness can be measured by the volume of oxygen you
can consume while exercising at your maximum capacity. VO2 max is the
maximum amount of oxygen in milliliters, one can use in one minute per
kilogram of body weight. Those who are more fit have higher VO2 max values
and can exercise more intensely than those who are not as well conditioned.
Numerous studies show that you can increase your VO2 max by working out at
an intensity that raises your heart rate to between 65 and 85 per cent of
its maximum for at least 20 minutes three to five times a week. A mean value
of VO2 max for male athletes is about 3.5 litres/minute and for female
athletes it is about 2.7 litres/minute.
Factors affecting VO2 max
The physical limitations that restrict the rate at
which energy can be released aerobically are dependent upon:
- the chemical ability of the muscular cellular
tissue system to use oxygen in breaking down fuels
- the combined ability of cardiovascular and
pulmonary systems to transport the oxygen to the muscular tissue system
Improving your VO2 max
The following are samples of Astrands (a work
physiologists) workouts for improving oxygen uptake :
- (1) - Run at maximum speed for 5 minutes. Note
the distance covered in that time. Let us assume that the distance
achieved is 1900 metres. Rest for five minutes, and then run the distance
(1900m) 20% slower, in other words in six minutes, with 30 seconds rest,
repeated many times. This is equal to your 10K pace
- (2) - Run at maximum speed for four minutes.
Note the distance covered in that time. Rest for four minutes. In this
case we will assume the you run a distance of 1500m. Now run the same
distance 15% slower, in other words in 4 minutes 36 seconds, with 45
seconds rest, repeated several times. This approximates to a time between
the athlete's 5K and 10K time
- (3) - Run at maximum effort for three minute.
Note the distance covered in that time. The distance covered is, say
1000m. Successive runs at that distance are taken 10% slower or at 3
minutes 18 seconds, with 60 seconds rest, repeated several times. This
approximates to your 5K time
- (4) - Run at maximum effort for five minutes.
Note the distance covered in that time. The distance covered is 1900m.
Rest five minutes. The distance is now covered 5% slower with one and a
half minutes rest. This is approximately 3K pace for you, i.e., five
minutes 15 seconds/1900m
- (5) - Run at maximum effort for three minutes.
The distance covered is 1100m. When recovered, he runs the same distance 5
per cent slower, i.e., three minutes nine seconds/1100m, with one minute
rest, repeated several times. This is at 3K pace
When and how often
It is suggested that in the winter sessions (1) and
(2) are done weekly, and in the track season sessions (3), (4) and (5) are
done weekly by runners from 800m to the half-marathon. Although it would be
convenient to use the original distance marks made by the duration efforts,
this doesn't take into account the athlete's condition before each session,
so the maximum effort runs must be done on each occasion when they may be
either more or less than the previous distance run. The maximum duration
efforts are in themselves quality sessions. If the pulse rate has not
recovered to 120 beats per minute in the rest times given, the recovery
period should be extended before the repetitions are started. The recovery
times between the reps should be strictly adhered to. These workouts make a
refreshing change from repetition running. When all four sessions are
completed within a month, experience shows substantial improvements in
performance.
Ideal VO2 max scores for various sports
|
Vo2 max |
Sport |
| >75 ml/kg/min |
Endurance Runners and Cyclists |
| 65 ml/kg/min |
Squash |
| 60-65 ml/kg/min |
Football (male) |
| 55 ml/kg/min |
Rugby |
| 50 ml/kg/min |
Volleyball (female) |
| 50 ml/kg/min |
Baseball (male) |
VO2 max Tests
An estimate of your VO2 max can be determined using
the following tests:
VO2 max Assessment
% MHR and %VO2 Max
It is possible to estimate your exercise intensity
as a percentage of
VO2 Max from your training heart rate.
David Swain (1994) and his US based research team using statistical
procedures examined the relationship between %MHR and %VO2 Max. Their
results led to the following regression equation :
- %MHR=0.64 * %VO2 Max + 37
The relationship has been shown to hold true across
sex, age and activity.
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By kind permission of:
Brian Mackenzie - (United Kingdom) UK Athletics Senior Track and Field Coach
(UKA4)
©
www.brianmac.demon.co.uk
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