Dr. James Manos (MD)
October 23, 2015
Regular aerobic exercise benefits the cardiovascular system!
Note: in this text, the writer expresses his point of view. Some advice is empirical, so you should consult your family doctor beforehand.
Regular aerobic exercise
· Competitive team sports like football and rugby predispose to injuries. Rugby is an aggressive sport where injuries are common. The Aussie (Australian) football (it is like American rugby but has many differences; the ball is the same) is very dangerous, as the athletes don’t wear protective equipment.
· For working out, you may register at a gym or a sports center.
· The cardiologists recommend, for healthy circulation, mild to moderate AEROBIC exercise at least 30 min daily, at least 5 days weekly. I recommend at least 1 day of abstention from aerobic exercises (e.g., on Sunday) to give the muscles and ligaments a chance to recover & self-heal from minor injuries. However, for weightlifting and weight exercises with machines, I recommend 2 days of absence, one in the middle of the week (e.g., on Wednesday) and one on Sunday, to give the opportunity for self-healing of minor soft tissue (muscles & ligaments) injuries.
· A prospective follow–up of a large study (‘the Copenhagen City Heart Study’) in 1,098 healthy joggers in Copenhagen, Denmark, that was published in February 2015 showed that aerobic exercise such as jogging for at least 2 – 3 days weekly in a total of 1 – 2.4 hours weekly is sufficient for being beneficial for our health, compared with people who follow a sedentary life and don’t exercise with jogging. According to the study, the optimal pace was slow to average. The lowest hazard ratio (HZ) for mortality was found in light joggers, followed by moderate and strenuous joggers! The study concluded that its findings suggest a U-shaped association between all-cause mortality and dose of jogging as calibrated by pace, quantity, and frequency of jogging. Light and moderate joggers have lower mortality than sedentary non-joggers, whereas strenuous joggers have a mortality rate not statistically different from that of the sedentary group (Reference: http://www.ncbi.nlm.nih.gov/pubmed/25660917 ).
· The concept of the above study is that instead of not exercising at all, you can exercise, such as jogging, 2 – 3 days weekly for a total of 1 – 2,4 hours weekly, and you should prefer mild to moderate exercise. Thus, strenuous exercise is discouraged! My personal lower limit is 3 times weekly for aerobic exercises & for anaerobic exercises as well. Anaerobic exercises, like weightlifting, may predispose to injuries.
· Aerobic exercise is beneficial for circulation, as it decreases blood lipids such as cholesterol & triglycerides, increases HDL cholesterol (also known as ‘good’ cholesterol), makes muscle pump of the gastrocnemius (a muscle in our shin) work, helps the return of the blood from the legs to the heart (only when the exercises involve the legs), lower blood pressure and blood sugar (thus are essential for people with diabetes & hypertension) and protect the heart by decreasing the stiffness of the arteries and improving arterial compliance, preventing coronary artery disease (CAD) that may cause a heart attack.
· Physical activity practices benefit obesity and related disorders such as hypertension (high blood pressure) and dyslipidemia (increased blood fats). A study investigated the effects of 6 and 12 months of moderate physical training on the levels of adipokines and cardiovascular disease (CVD) markers in normal-weight, overweight and obese volunteers. The 143 participants were followed up at baseline and after six and twelfth months of moderate regular exercise, 2 times a week, for 12 months. The volunteers were distributed into 3 groups: Normal Weight Group (NWG,), Overweight Group (OVG), and Obese Group (OBG). No significant changes in anthropometric parameters and body composition were observed in any groups following 6 and 12 months of exercise training. Before the training, Leptin, IL-6 levels, and systolic blood pressure were significantly elevated in OBG. Regular exercise decreased HDL-c (‘good’ cholesterol), leptin, adiponectin, resistin levels, and diastolic blood pressure in OVG. In OBG, exercise diminished HDL-c, homocysteine, leptin, resistin, IL-6, and adiponectin. Moderate exercise had no effect on the body composition; however, exercise did promote beneficial effects on the low-grade inflammatory state and cardiovascular disease (CVD) clinical markers in overweight and obese individuals (Reference: http://www.ncbi.nlm.nih.gov/pubmed/26474157 ).
· It has been conclusively shown that a single episode of aerobic exercise reduces ambulatory blood pressure in hypertensive patients. Similarly, regular aerobic training also decreases ambulatory blood pressure in hypertensive individuals. Based on current knowledge, aerobic training should be recommended to decrease ambulatory blood pressure in hypertensive (with high blood pressure) individuals. At the same time, resistance exercise could be prescribed as a complementary strategy (Reference: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2845774/ ).
· Exercise-induced increases in the peripheral beta-endorphin (a natural painkiller similar to morphine that fights pain & depression) concentration is mainly associated with changes in pain perception and mood state and possibly substrate metabolism. In endurance exercise performed at a steady state between lactate production and elimination, blood beta-endorphin levels do not increase until exercise duration exceeds approximately 1 hour, with the increase being exponential thereafter. Beta-endorphin and ACTH are secreted simultaneously during exercise, followed by a delayed release of cortisol. These results support a possible role of beta-endorphin in changes in mood state and pain perception during endurance sports (Reference: http://www.ncbi.nlm.nih.gov/pubmed/1553453).
· The endocannabinoid system is known to have positive effects on depression partly through its actions on neurotrophins, such as Brain-Derived Neurotrophic Factor (BDNF). As BDNF is also considered the major candidate molecule for exercise-induced brain plasticity, the study's authors hypothesized that the endocannabinoid system represents a crucial signaling system mediating the beneficial antidepressant effects of exercise. A study investigated, in 11 healthy trained male cyclists, the effects of an intense exercise (60 min at 55% followed by 30 min at 75% W(max)) on plasma levels of endocannabinoids (cannabinoids in the body that bind to cannabinoid receptors and have painkilling and mood-stabilizing effects) (anandamide, AEA and 2-arachidonoylglycerol, 2-AG) and their possible link with serum BDNF. AEA levels increased during exercise and the 15-minute recovery, whereas 2-AG concentrations remained stable. BDNF levels increased significantly during exercise and decreased during the 15 min of recovery. AEA and BDNF concentrations were positively correlated at the end of exercise and after the 15 min recovery, suggesting that AEA increment during exercise might be one of the factors involved in the exercise-induced increase in peripheral BDNF levels and that AEA elevated levels during recovery might delay the return of BDNF to basal levels. AEA production during exercise might be triggered by cortisol since the scientists found positive correlations between these two compounds and because corticosteroids are known to stimulate endocannabinoid biosynthesis. These findings provide evidence in humans that acute exercise represents a physiological stressor able to increase peripheral levels of the endocannabinoid anandamide (AEA) and that Brain-Derived Neurotrophic Factor (BDNF) might be a mechanism by which AEA influences the neuroplastic and antidepressant effects of exercise (Reference: http://www.ncbi.nlm.nih.gov/pubmed/22029953 ).
· Regular aerobic exercise helps in losing weight.
· About how many calories you can lose with exercise, you can visit the online calculator on http://www.cancer.org/healthy/toolsandcalculators/calculators/app/exercise-counts-calculator
· Right after you stop exercising, take your pulse: place the tips of your first two fingers lightly over one of the blood vessels on your neck, just to the left or right of your Adam's apple. You may also try the pulse spot inside your wrist just below the base of your thumb. For calculating the pulses per minute, count your pulse for 10 seconds and multiply the number by 6 (as 1 minute is 60 sec). Check your pulse periodically to see if you exercise within your target zone. As you get in better shape, try exercising within the upper range of your target zone.
· During exercise, the heart rate (HR) should not reach the maximum (220 – age) but within the target zone of 50 – 85% of the average (related to age) maximum heart rate. During the first few weeks of working out, aim for the lower range of your target zone (50%) and gradually build up to the higher range (85%). After six months or more, you may be able to exercise comfortably at up to 85 percent of your maximum heart rate (Reference (Retrieved October 7, 2015): http://www.heart.org/HEARTORG/GettingHealthy/PhysicalActivity/FitnessBasics/Target-Heart-Rates_UCM_434341_Article.jsp and http://www.cancer.org/healthy/toolsandcalculators/calculators/app/target-heart-rate-calculator ).
· For an online calculator of the target heart rate on the exercise, you may visit the site http://www.cancer.org/healthy/toolsandcalculators/calculators/app/target-heart-rate-calculator
· Running on the treadmill is excellent ‘cardio’ training, i.e., it is excellent for a healthy cardiovascular system and helps lose weight.
· Other particularly good ‘cardio’ exercises that benefit the heart are the elliptical machine or jumping rope (as boxers do). One professor of mine also added ‘rowing’ as an excellent ‘cardio’ exercise. However, to my mind, it may harm the lower back.
· Step and cycling are good only for the legs, as the upper body does not work. I personally recommend cycling only to the elderly! The elderly can go jogging, but if they find it difficult (e.g., because of arthritis), they may walk fast.
· People who like jogging should never do it on a firm surface, e.g., on the cement of the street or the marble of the pavement, as many people do by jogging on the pavement instead of jogging in a park. They also breathe polluted air! The surface may be soil but without stones that may cause injuries. A hard running surface, such as cement, may cause injuries to the ligaments and tendons of the knees and predispose them to osteoarthritis. The ideal surface is the special running track surface/ flooring that many gyms and sports centers/ stadiums are equipped with.
· Treadmill is an important ‘cardio’ exercise. As a doctor & physical therapist, the program I recommend is the following: Start with 5 min of pacing (I start with 4 mph) with zero inclines, and every minute, increase velocity until 6 – 6.5 mph (miles per hour). When you reach this level, you will be forced to run. Increase incline to 1%. Then gradually – every 1 – 2 min – increase speed and incline until a maximum speed of 8 mph and a maximum incline of 3%. Stay for some min (e.g., 2 – 5 min) at this speed & incline, then gradually decrease speed & incline every 1 – 2 min. When you reach 6 mph, you can continue pacing with zero inclines. You will complete with pacing for 3 – 5 min, decreasing speed & incline every 1 – 2 min until the level of 4 mph. Then you will continue pacing with increasing speed & incline until 6 – 6.5 mph, and you will continue jogging with increasing speed & incline every 1 – 2 min until the above limit (speed 8 mph, incline 3%) in which you will continue for some min (e.g., 2 – 5 min) and then every 1 – 2 min you will decrease speed & incline, continue with pacing with zero inclines when you reach the level of 6 mph and eventually you will finish with cool down with pacing with decreasing speed every 1 – 2 min. This scheme is the double pyramid that, to my mind, is ideal as it gradually increases energy and heart rate to a maximum level. After this, the energy gradually decreases until pacing. The pyramid is repeated by gradually increasing and then decreasing speed & incline. The scheme finishes with a 5-minute cooldown with pacing with zero inclines and a gradual decrease in velocity. If you exercise for longer than 30 min, you may do a triple pyramid.
· High incline (more than 3 – 4%) on the treadmill and jogging on a solid surface (e.g., the cement of a street or the marble) burdens the knee joint, may cause injuries to the tendons & ligament of the knee and hip, and may predispose to knee osteoarthritis. It also may cause injuries in tendons, ligaments, and muscles in the body, stress fracture in the shin bones and foot, and may cause back pain, foot pain from disturbance of plantar muscles, and injury to muscles such as the hamstrings and the quadriceps.
· There is no consensus about which incline slope is safer on treadmills. In any case, we should prefer a low incline. I recommend a maximum 3% incline, but a study below showed that 4% is OK. A study in well–trained distance runners concluded that incline treadmill training is effective for improving the components of RE but insufficient as a resistance-to-movement exercise for enhancing muscle power output (Reference: http://www.ncbi.nlm.nih.gov/pubmed/24172721 ). A crossover study in 2010 with 3 D –k motion analysis examined nineteen healthy young runners/joggers (age = 25.3 +/- 2.5 years). Participants ran at 3.13 m/s on a treadmill under 3 different running surface slope conditions: 4 degrees decline, level, and 4 degrees incline. The study showed that moderate changes in running surface slope had a minimal effect on the ankle, knee, and hip joint kinetics when velocity was held constant. Only changes in knee power absorption (increased with decline-slope running) and hip power (increased generation on incline-slope running and increased absorption on decline-slope running in early stance) were noted. The scientists observed an increase only in the impact peak of the vertical ground reaction force component during decline-slope running, whereas the non-vertical components displayed no differences. The study concluded that running style modifications associated with running on moderate slopes did not manifest as changes in 3-dimensional joint moments or in the active peaks of the ground reaction force. The data indicate that running on level and moderately inclined slopes appears to be a safe component of training regimens and return-to-run protocols after injury (Reference: http://www.ncbi.nlm.nih.gov/pubmed/20064043 ).
· Sneakers with full–length air – cushions are very good for jogging/ running and daily use, as the foot is supported by the cushion.
· Warming up before exercise is essential to avoid muscle & ligament injury and to give the heart a chance to gradually increase its beat rate. The warm-up should include a physical activity where all muscles work, e.g., fast walking or running on the treadmill, the elliptical machine, or jumping rope (as boxers do). Warming up should be done for at least 5 minutes.
· After warming up, muscle stretching is essential for preventing ligament and muscle injuries. It should be done for 10 – 15 min and should include the muscles of the arms and legs. You may consult a physiotherapist who can show you these techniques.
· After stretching, a brief warm-up is needed, e.g., jogging for 5 minutes. Then you can start exercise, e.g., weightlifting.
· After completing the exercises (such as weightlifting), a brief cool down (e.g., with slow jogging) and stretching are also important.
· Most people do exercises, especially weight exercises & abdominal working out, wrong.
· Many people in the gym cheat during exercises, e.g., making an exercise fast, not completing the full range of motion, using other auxiliary muscles, etc.
· Classically, most people do the abdominal crunches wrong. They do the exercise in a supine position. With the knees bent, they bend the trunk more than 45 degrees, so they mostly do the exercise by working the muscles of the legs (quadriceps) instead of the abdominals (abs)! The abdominal muscles work only when we bring our chin to our chest and bend our trunk less than 45 degrees so that we just raise the inferior angles (the angles on the lower part) of our scapulae (shoulder blades) from the floor. That is what I was taught in physical therapy school.
· The abdominal exercise with leg lifting in the supine position may harm the back, causing back pain.
· In excess sweating, water, sugar (also called dextrose) & electrolyte (especially sodium & potassium) replacement may be needed to avoid dehydration. Special electrolyte replacement solutions can be found in chemists or supermarkets (energy drinks). However, self–treatment is not recommended, as severe dehydration needs emergency hospital care. Sports drinks may cover the loss of electrolytes & sugar. Plenty of water is also needed. In the market, someone may buy an energy sports drink that contains dextrose (sugar) and electrolytes (e.g., Lucozade (TM) is a famous brand). However, avoid drinks with caffeine & taurine, as they may increase heartbeat (taurine may also lower blood pressure).
· In anaerobic exercise, few repetitions (e.g., less than 8) offer muscle hypertrophy (enlargement); more repetitions (e.g., more than 8) offer a leaner muscle body without muscle hypertrophy. On weight exercise, the muscle cells do not increase in number but in size as they sustain hypertrophy (enlargement). It is the connective tissue that enlarges, not the muscle fiber.
· The disadvantages of anaerobic exercise include the increase in blood pressure during exercise and its consequences in the heart on high risk for coronary artery disease (CAD) people (especially in those with stenosed (narrowed) coronary arteries of the heart), as well as the risk of severe arrhythmias and the risk of aneurysm rupture on people with brain or aorta (chest or abdominal) aneurysm; the increased risk for injuries on muscles, tendons, ligaments, and joints; the increased oxidative stress; the increased lactate levels (that cause exhaustion); and the absence of benefits to the heart and generally the cardiovascular system. However, recent studies have shown that resistance and isometric training may, in fact, decrease blood pressure. Another benefit is that they may prevent osteoporosis in post-menopausal (after menopause) women.
· Anaerobic exercise is contraindicated in people with medical problems such as hypertension, hernia, aneurysm (in the brain or abdominal or chest), back pain, etc. Weightlifting, especially when done wrong, may cause severe back pain and induce disc problems (discopathy with disc – the cushion between the vertebra of the spine that acts as a shock absorber for the pressure forces tension – prolapse that may pressure spinal nerves causing back pain that may be radiated to the leg – called sciatica) that may cause permanent back pain. The worst weight exercise for causing back pain, although many men like it to have strong buttocks, is squatting. Also, abdominal muscle exercise by leg lifting (with the knees extended) in a supine position may also cause back pain.
· Professional, long-term physical training is often associated with morphological and metabolic changes in the heart. A study assessed the left ventricular (LV) and right ventricular (RV) heart morphology and function and the LV high-energy phosphates of athletes trained in sustained power or aerobic exercise. The study concluded that athletes' left ventricular (LV) and right ventricular (RV) hypertrophy is associated with normal systolic and diastolic functions and resting cardiac energy metabolism, supporting its benign nature. A more pronounced RV dilatation was found in the anaerobic power athletes, and further investigation is warranted to establish the clinical significance of this training effect (Reference: http://www.ncbi.nlm.nih.gov/pubmed/17967601 ).
· Exercise-induced arterial hypertension (EIAH) leads to myocardial (heart muscle) hypertrophy and is associated with a poor prognosis. EIAH might be related to the "cardiac fatigue" caused by endurance training. A study examined whether there is any relationship between EIAH and left ventricular hypertrophy in Ironman triathletes. Scientists used echocardiography and spiroergometry to determine the left ventricular mass (LVM), the aerobic/anaerobic thresholds, and the steady-state blood pressure of 51 healthy male triathletes. The study concluded that significant left ventricular hypertrophy with left ventricular mass (LVM) >220g is associated with higher arterial blood pressure at the aerobic or anaerobic threshold. Endurance athletes with exercise-induced arterial hypertension (EIAH) may require therapeutic intervention to at least prevent extensive stiffening of the heart muscle and exercise-induced cardiac fatigue (Reference: http://www.ncbi.nlm.nih.gov/pubmed/25132960 ).
· Besides having health-promoting effects, exercise is considered to induce oxidative stress. A study investigated the effects of aerobic and anaerobic exercise on a series of oxidative damage markers. The study's findings suggest that similar workloads of anaerobic exercise and aerobic exercise induce reactive oxygen species (ROS) differently: aerobic exercise initially generates more ROS, whereas anaerobic exercise may induce prolonged ROS generation. Although more oxygen was consumed during aerobic exercise, ROS generated did not induce significant oxidative damage. Oxygen consumption per se may not be the major cause of exercise-induced oxidative damage
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