1.3 Exercise Flashcards
Aerobic exercise
Aerobic exercise occurs with a low to moderate demand for energy.
Exercise can take place aerobically (using oxygen) to transfer energy to muscles; glucose is reacted with oxygen in this process.
Glucose + oxygen → energy + carbon dioxide + water
Aerobic respiration releases more energy per glucose molecule than anaerobic because the glucose is fully broken down
Anaerobic exercise
Anaerobic exercise involves high-intensity activities such as sprinting and heavy weightlifting.
Exercise taking place anaerobically (without oxygen) can still transfer energy to muscles; it simply involves the incomplete breakdown of glucose into lactic acid.
A build-up of lactic acid can cause muscle fatigue and pain, and exercise will need to stop after a short time.
Glucose → energy + lactic acid
Oxygen debt
It is the amount of extra oxygen the body needs after exercise to react with the accumulated lactic acid and remove it from the cells.
The body can deal with lactic acid in two ways.
It can be oxidised (react with oxygen) to form carbon dioxide and water - the same products formed in aerobic respiration.
Alternatively blood flowing through the muscles transport the lactic acid back to the liver where it is converted back to glucose.
Recovery
After vigorous exercise the participant needs to recover, this helps to avoid excessive fatigue, potential nausea, muscle soreness and cramps.
Cool down
Five to ten minutes of walking or jogging whilst maintaining an elevated breathing rate can be an effective cool down, followed by another five to ten minutes of stretching.
The benefits of a cool down include:
decrease in body temperature
removal of lactic acid
reduction in DOMS (delayed onset muscle soreness)
decrease in dizziness or nausea
returning heart rate and breathing rate to resting by maintaining blood flow
Diet (rehydration)
Rehydration is the replacement of fluids and minerals lost from sweating during exercise.
It is not just the replacement of water that is required, minerals also need to be replaced as these are lost as part of sweat evaporating from the surface of the skin.
Recovery drinks can be consumed which contain the minerals necessary, plus water, for good recovery.
Diet (Glucose)
Glucose must also be replaced as this is broken down to release energy for muscles during aerobic and anaerobic exercise.
Glucose is a carbohydrate, so to aid recovery a participant should consume carbohydrates following strenuous exercise, this could be added to fluids or consumed as part of a meal or snack.
Ice bath
An ice bath can be used to aid recovery.
Intense exercise can cause muscle tissue to tear which can contribute to and cause DOMS.
Research suggests that ice baths aid recovery by:
Causing blood vessels to constrict and push out waste products such as lactic acid.
Reducing swelling.
Promoting increased blood flow to muscles after the ice bath has finished.
Massage
During massage, muscles and joints are rubbed and kneaded by the hands (usually of a sports massage therapist or physiotherapist), or by dedicated equipment such as an electric handheld massager.
This can help reduce pain and swelling and reduce DOMS as it stimulates blood flow and prevents muscle fatigue and stiffness.
Immediate effect of exercise
Heart rate increases - Normal resting heart rate is approximately 70-80 beats per minute, during exercise, this raises to 100-150 beats per minute (this will vary depending on the intensity and duration of the exercise).
Contractions of the heart increase and are more powerful which increases the stroke volume.
The rate and depth of breathing increases.
This ensures that efficient gas exchange in the lungs can still take place.
Increased body temperature - An increase in muscle contractions during exercise will release more heat energy.
The effects of this can be seen in sweating which releases heat energy at the skin surface by evaporation of sweat. Skin may also look red due to blood vessels at the surface of the skin dilating to release heat energy by radiation.
Short term effect of exercise
Where changes happen up to 36 hours after exercise, this is considered a short-term effect of exercise.
Tiredness/fatigue - the muscles have been working hard and become swollen and feel heavy which can lead to tiredness. This sensation can also be caused by muscles using up stores of carbohydrates during respiration and the energy supply is reduced.
Light-headedness - this can also present as feeling dizzy; this is often due to low blood sugar or low blood pressure.
Nausea (feeling sick) - if the participant has overexerted themselves during exercise this can leave them feeling nauseous as blood is directed away from the stomach and digestive organs to the heart and lungs.
Delayed onset muscle soreness (DOMS) - occurs because of small tears in the muscle that happens during exercise that cause swelling and soreness in the muscles.
Cramps - caused by involuntary contractions of muscle that happen because of fatigue; dehydration and loss of minerals can contribute to cramps (not the same as DOMS).
Long term effect of exercise
Exercise is considered long-term when participants sustain regular exercise for months or even years.
Change in body shape - this could be a decrease in body mass due to fat stores being used to provide glucose needed for energy. Anaerobic exercises can increase the size of muscles involved in the exercise: this is known as hypertrophy and can alter the shape of the body.
Increase in muscle strength - anaerobic exercises such as weight lifting can improve the strength of the muscles involved.
Improvement in muscle endurance - this occurs due to repeated exercise such as sit-ups, the muscles involved will be able to endure more exercise over time.
Joints become more stable and supple -the muscles, tendons and ligaments surrounding joints will get stronger and so joints are supported better. Over time joints will become more flexible and suppleness will improve.
Increase in speed - anaerobic exercises such as sprinting will increase the speed of participants with regular training.
Improvement in cardiovascular endurance - this comes from slower aerobic exercises, such as swimming, where endurance is built up and stamina also improves.
Increase in heart size - this is an example of hypertrophy. This heart is a muscle so repeated working of the heart will increase the size of the muscle tissue.
Decrease in resting heart rate - this is known as bradycardia and can occur after prolonged exercise for months or years. Stroke volume will increase with regular exercise so heart rate must decrease to ensure cardiac output is kept the same.
