EFFECT OF EXERCISE ON DIABETES
Increased blood pressure or hypertension is one of the most common problems faced these days. With time this is further increasing due to various factors such as sedentary lifestyle, food choices, and lack of knowledge, unnecessary medication, and disturbed sleep. There are other factors such as hereditary, diseases or aging which at times are not within the control of a person despite all the measures. Here a person may not be able to prevent but can prevent the onset of Hypertension.
Reasons causing the increase in Blood pressure
To understand this we need to understand how we measure heart functioning. The work done by our heart is called ‘Cardio Output’. This simply means the amount of work our heart has to do to pump the blood so that it reaches all arteries and arterioles. This ‘Cardio Output’ is a simple function of ‘Heart Rate’ and ‘Stroke Volume’. Stroke volume is simply the amount of blood pumped by our heat in a minute.
Cardio Output = Heart rate X Stroke Volume
Understanding this much we can now list three major reasons leading to Hypertension or High blood pressure.
- High heart rate
- High Stroke Volume
- More resistance in our arteries and arterioles (Total Peripheral Resistance – TPR)
Stroke volume and our weight
We all know that our body is 70% water. But have we ever thought of the relationship of our weight (Total body mass) with the quantity of blood we have in our body? We will not go into depth at this point about how and why high BMI will lead to higher TPR. Also instead of going into too much depth about how we reached to a formula, we simply try and draw a rough figure. This will be an approximation of total blood available in the body.
We also need to remember that women have less plasma volume than men. Women’s plasma volume can increase by 50% during pregnancy.
Plasma volume = (70% X Body mass) X 1/12
The result will be within 20% of the actual volume. So we can establish here that Plasma Volume is directly proportional to body mass. Higher body mass will need more plasma volume to maintain all tissues and cells.
Heart rate factors
If we exclude an increase in heart rate during exercise, we can list factors as to why some people have higher heart rates during rest or normal activity whereas other have low. The rest heart rate of an endurance athlete can go below 50 beats per minute. Normal figures are 72 beats per minute.
The amount of force the heart generates when it pumps once will determine the pressure it can generate for blood to reach everywhere in the body. Now, if our heart is not able to generate enough force however the stroke volume remains the same, the heart has to beat more times to increase cardio output. Hence we have a higher heartbeat in cases where the heart is less healthy. Taking the same example in an endurance athlete the heart is so healthy that in a single beat it can pump more blood leading to a lesser heart rate.
Controlling Hypertension without medication
Let us see how we can control each factor one by one
Lowering Heart Rate
We simply have to add some cardio workouts to our lifestyle to increase the efficiency of our hearts. Since we all know that the heart is just a muscle, so we can build its strength. Fortunately, the heart is a very efficient system and it responds quickly. A simple cardio workout that helps to keep your heart rate at or above 60% of your maximum permitted ( Max Permitted is 220 – age) for 15 minutes thrice a week can significantly lower the BP by 02 scales if done regularly for 3 months. Continue doing it beyond 6 months will reduce BP by 05 scales. However, as the heart trains fast, it also de-trains fast. So if you miss 2 weeks for any reason, the results will start diminishing.
Reducing stroke volume
We have established the fact that plasma volume is directly proportional to body weight. So if we reduce body weight, plasma volume will come down. Each KG reduced will reduce plasma volume by about 1.5 to 2% up to a minimum value. This reduction will reduce volume pumped and hence the cardio output of the heart leading to lower blood pressure.
The salt we eat is also responsible for plasma volume. Our hypothalamus has a set point for the density of Sodium (Na) in our blood. So if we eat more Sodium based salt, salt concentration will increase. To bring its density to a set point, our brain will control the kidney’s output so that plasma volume is increased leading to sodium concentration equal to set point figures. Potassium plays the opposite role. It is present inside the cell and generally exchanges with sodium movements. Since potassium reduces plasma volume it is also dangerous. If taken in larger quantity or as a supplement can lead to heart failure.
To decrease stroke volume we can do three things:-
Reduce salt intake
Increase dietary sources of potassium such as bananas, tomatoes, coconut water, etc.
Reducing Total Peripheral Resistance (TPR)
This is mainly caused if the area of cross-section of our arteries reduces because of various factors. Also due to excessive fat deposits, our arterioles have to travel longer to supply blood to all fat depositing tissues, leading to an increase in resistance. It is easy to reduce TPR by making lifestyle changes such as
- Increase in physical activity
- Reduce body fat percentage
- Stop processed food
- Swap saturated fat with unsaturated fat and reduce overall consumption of fat
- Result of the combined effect
In various studies and researches it has been proved that if someone takes all the three measures as mentioned above, systolic blood pressure will come down 05 scales in just one month, and mean arterial pressure will also reduce. Practicing the same over a longer period (6 months or more) will bring a prehypertension case into the normal range. Those who are already suffering from hypertension and are taking medication should start all the above recommendations. Then under medical supervision can reduce medication slowly and ultimately stop once they reach normal range. It is important to believe that one can stop taking medicine to reduce blood pressure by understanding the science behind it.