In the first part of this blog about Wellness and Longevity we looked at diet. Namely how having a healthy out look towards food & nutrition helps to shape a healthy lifestyle. Which in turn contributes to our Wellness and Longevity. In the second part of this blog we’re going to look at exercise.
In today’s sedentary lifestyle exercise and moving regularly is not always the norm. Many of us have desk based jobs which can involve being stationary and seated for prolonged periods of time. Combine this with most people commuting to get to work which again involves (you guess it!) being seated, whether we’re driving or catching public transport. This can equate to anything between 60-80 hours a week being seated and that’s just look at work and commuting!!
The NHS’s current guidelines advise for 150 minutes of moderate aerobic activity (such as walking) and two strength sessions a week, or 75 minutes of vigorous aerobic activity (such as running) and two strength sessions a week. Notice the general themes of this guidance? A combination of aerobic training and strength training, and this guidance is for the general public not someone training for a specific event (like a 10k run or half marathon) or goal. So, what are the physiological benefits of aerobic and strength training? Well let’s start with the long term physiological adaptions and benefits of aerobic training
Maximal Oxygen Uptake (VO2max) Maximal oxygen uptake is one of the gold standards of aerobic fitness testing and increases during training due to increases in stroke volume, cardiac output and a small increase in arteriovenous difference. Aerobic training will elicit the greatest changes in VO2max and in the first six months of training increases of 10-30% are often seen. The more highly trained an athlete is however, the less potential there remains for further increases in VO2max.
Adaptations of the Heart – Increased Stroke Volume – More blood will be pumped per beat. Aerobic training causes the heart’s stroke volume to increase during both rest and physical activity. The key factors in this adaptation are increased Left Ventricle volume, reduced cardiac and arterial stiffness, increased diastolic filling time and improved cardiac contractile function. In short, the heart muscle become hypertrophied
Left Ventricular eccentric hypertrophy – During prolonged aerobic exercise the resulting increase in venous return and cardiac preload causes periods where the heart’s chambers are expanded. This causes the myocardial tissue to adapt resulting in stronger ventricle walls and a larger capacity of the heart. While strength training may elicit some myocardial changes to the heart it is not as significant as the adaptions that take place from aerobic training
Increased Frank-Starling Mechanism – The ability of the heart to change its force of contraction and therefore stroke volume in response to changes in venous return is called the Frank Starling Mechanism. This mechanism is enhanced with aerobic training as the hypertrophic and chamber volume adaptations that result from regular aerobic exercise are made by the addition of new sarcomeres in the cardiac muscle that maintain or even increase the stretching action of the tissue during diastole (filling of the heart with blood).
Lower Resting Heart Rate and Training-induced bradycardia – Regular Aerobic Training has been shown to reduce the resting heart rate as a result of the heart becoming stronger and being able to pump more blood around the body per contraction (beat). Bardycardia is a low resting heart rate (<60 beats per minute). When present in healthy, trained individuals is a consequence of increased stroke volume with unchanged cardiac output at rest or submaximal intensities
Adaptations of the Blood – Increased Total Blood Volume – Increased total blood volume is a critical adaptation that allows stroke volume to increase via the Frank-Starling Mechanism.
Plasma Volume Increase – During exercise, plasma volume can decrease by around 10% while taking part in strength based training and up to 20% while training aerobically. As blood pressure increases with exercise, water is forced from the blood into the interstitial spaces and with increased duration of exercise, fluid loss from perspiration can cause further decreases in plasma volume. With even the first workout however, adaptations occur that increase the plasma volume post-workout. Within the first few weeks of a new training programme plasma volume can increase 12-20% and endurance athletes can have blood volume ~ 35% greater than untrained individuals.
Increased Red Blood Cells – Initially, there are no changes in the number of red blood cells and the increase in blood volume that occurs in the first few days of training is a result of the increases in plasma mentioned above. Eventually, red blood cells count does increase to ensure that the oxygen carrying capacity of the blood is maintained however the percentage increase does not match that of plasma, reducing the haematocrit and decreasing blood viscosity which in turn is an aid to improved blood flow.
Arteriogenesis and Angiogenesis - Aerobic training can result in exercise induced vascular remodelling. Arteriogenesis is the enlarging of existing arterial vessels and allows for increased blood flow to the periphery of the vascular system. Angiogenesis is the formation of new capillaries. This denser capillary network results in improved gas diffusion and an increased mean transit time for red blood cells that travel through the exercising muscle, both features which contribute to higher oxygen extraction levels in trained individuals. Angiogenesis can also allow for greater nutrient delivery over a longer period of time.
Improved Blood Distribution – With prolonged aerobic training the body becomes more efficient at submaximal intensities of exercise and therefore requires relatively less redistribution of blood flow allowing for less restriction of blood flow to the abdominal organs and kidneys.
Reduced Blood Pressure An individual with normal blood pressure may not see much change in BP following aerobic training, however a hypertensive individual may see small but significant decreases. Research suggests that both aerobic training and resistance training can have a beneficial effect on blood pressure, with aerobic training reducing SBP by 3-5 mmHg and DBP by 2-3mmHg with just a 3 mmHg reduction in BP decreasing the risk of CV disease by 5-9% and stroke by 8-14%
Adaptations of the Lungs There is little change in lung volume and capacity with aerobic training. Although Tidal Volume and Pulmonary Diffusion do not change at rest or during sub-maximal exercise, endurance training can increase the capacity of both at maximal intensities.
Adaptions of Skeletal Muscle – Increased Mitochondrial Mass Approximately 4-7% of skeletal muscle volume comprises mitochondria and aerobic training can increase the mitochondrial density in muscle by up to 40%. There are exercise-induced biochemical and morphological changes that take place and both combine to increase the oxidative capacity of skeletal muscle.
Increase in Muscle Mass – Resistance based exercise results in the both the growth of the muscles fibres and the increase in the number of muscle fibres in the belly of the muscle depending on the type of strength training being performed. Strength training also improves the neural drive of the muscles being used resulting in better recruitment of the muscle fibres required to perform a movement.
Reduction or Reversal of Sarcopenia – People who are physically inactive can lose as much as 3 percent to 5 percent of their muscle mass per decade after age 30. Sarcopenia is the gradual loss of muscle mass with age. Research has shown that a program of progressive resistance training exercises that build muscle fast can improve sarcopenia in as little as two weeks.
Increase in Bone Density Increasing bone density – Muscle loss is closely associated with bone density loss, but fortunately, strength training increases both muscle mass and bone mass. Substantial increases in bone mineral density have been seen after several months of regular strength training. A study performed in the early 90’s found that the bone mass density of men aged 40-50 who participated in strength based exercise such as powerlifting had between 7-15% greater levels of bone density in their pelvis and spine that compared to the sedentary study group of men at the same age.
Recharging metabolism – Resistance training has a dual impact on a person’s metabolic rate because it increases energy use during both the exercise session and the muscle recovery and rebuilding period, for up to three days after each session.
Improving blood lipid profiles - Obesity in the UK is at an all time high and is one of the main preventable cause of cancer according to Cancer Research UK. Regular strength training can result in favourable increases of 8 to 21 percent in HDL (good) cholesterol, favourable decreases of 13 to 23 percent in LDL (bad) cholesterol, and favourable reductions of 11 to 18 percent in triglycerides.
Decreasing physical discomfort – While a large percentage of people with lower-back pain can reduce discomfort by activating strengthening their intrinsic core musculature, strength training has also proven helpful in alleviating long-term pain symptoms, for example in people who have arthritis and fibromyalgia.
Improved mental health – Several studies on the psychological changes associated with regular strength training demonstrate significant improvements in depression, physical self-concept, fatigue, revitalisation, and overall mood disturbance among adults and older adults. This is due to the release of endorphins as a result of exercising. Neurotransmitters such as dopamine, serotonin, oxytocin are associated with feeling of ‘happiness’ or alertness, are all released as a result of regular exercise. Runners call it the ‘runners high’.
At the start of this blog on Wellness and Longevity the purpose was to highlight the ways in which we can help improve our general wellness which helps to lead to increased longevity. With the average persons lifestyle being more sedentary than ever simply prevent is definitely better than cure. This short list is by no means exhausted but does help to highlight the significant number of health benefits that occur when we participate in regular aerobic and strength based training.