Garmin 910XT GPS triathlon watch, capable of real-time heart rate monitoring
Cycling intensity based on heart rate
Maximum heart rate = 220 - age (individual differences may occur, but the error is within an acceptable range for most people, so although this method is not the most accurate, it is the simplest and easiest to remember, and holds high reference value for the general public)
60%-70% is the aerobic zone
70%-80% is the mixed zone
80%-90% is the anaerobic zone
90%-100% is the limit zone
Under normal circumstances without long-term training, do not cycle in the limit zone. Entering the limit zone first puts significant strain on the heart, which may cause cardiac hypoxia and sudden stoppage. Moreover, in the limit zone, due to the high level of anaerobic respiration in muscle tissues, the body suffers from severe oxygen deficiency, inevitably leading to impaired consciousness, which affects the rider’s ability to control the bike and can easily result in loss of vehicle control. Therefore, beginners and those who do not exercise regularly should strictly avoid training in this zone.
Aerobic zone exercise:Exercise in the aerobic zone primarily burns fat. In this zone, the body utilizes fat stores for energy. The process usually burns fuel completely without producing large amounts of lactic acid. Exercise feels relatively easy, with smooth breathing. However, even in this zone, some carbohydrates are still burned—it’s not the case that only fat is being burned at these heart rates.
Mixed zone exercise:The body uses both fat and carbohydrates for energy production. Combustion is relatively complete, and does not produce large amounts of lactic acid. Exercising in this zone has higher energy output efficiency, and muscles do not feel particularly fatigued.
Anaerobic zone exercise:The body uses blood sugar, muscle glycogen, and liver glycogen for energy. In this zone, the body relies almost entirely on carbohydrates for fuel, burning them through anaerobic respiration and producing large amounts of lactic acid. Lactic acid stimulates the muscles, causing fatigue, which is why riders feel muscle soreness during this period.
Forms of energy storage in the body
Carbohydrates: Carbohydrates are one of the most basic energy substances in the body, heavily involved in daily metabolism, and serve as the main source of energy during anaerobic respiration. They are mainly stored in the body as blood glucose, muscle glycogen, and liver glycogen. Among these, glycogen reserves are crucial for a cyclist's endurance. Blood glucose remains relatively constant. Glucose is a monosaccharide (C6H12O6), while glycogen is a polysaccharide (C5H10O5)n that can be hydrolyzed into individual glucose molecules by adding water (H2O), thereby instantly replenishing glucose consumed during exercise. Glycogen in the body is mainly stored as muscle glycogen and liver glycogen, both of which can be increased through proper training and diet. Burning 1g of glucose produces 4.1 kilocalories of heat.
Fat: Fat is a high-grade form of energy storage in organisms and also serves to protect internal organs and absorb external impacts. Therefore, fat must exist in the human body. Fat is mainly involved in aerobic activities. Burning 1g of fat releases approximately 9 kilocalories of heat.
Protein: Protein is not a primary energy source for the body. It is only used extensively when there is a severe shortage of carbohydrates, and its metabolic byproducts can be quite harmful to the body, so such a situation should be strictly avoided. Burning 1g of protein produces about 4 kilocalories of heat, which is close to that of carbohydrates.
About knee protection
Whenever you experience any discomfort in your knees, stop cycling immediately, identify the cause of the pain, and rest until recovered before continuing. Otherwise, once serious knee injuries occur, they can be very difficult to heal, as the knee area has relatively low blood flow and heals slowly. If discomfort arises, wearing knee pads and massaging the area around the knees can help speed up recovery.