I. Comparison of Physical Changes Between Brisk Walking and Cycling
         1. Heart Rate – Very similar, with minimal difference
         2. Calorie Burn – At first glance, walking seems to burn more than twice the calories of cycling, but because the time spent differs, if you compare the average calorie burn per minute, the calorie expenditure of both is quite similar. The data for both are close, but relatively speaking, cycling feels much easier. (Because it's faster and you feel the wind, body temperature drops more easily, reducing fatigue.) Although cycling feels easier, in terms of heart rate changes, cycling causes greater fluctuations. Greater heart rate changes indicate a higher physical burden, meaning a higher workout intensity. Therefore, the benefit of cycling is that it feels easy, but your body can achieve a high level of exertion quickly!

        II. Key Findings on Cycling as Exercise
       Experimental Results:
         1. Brisk Walking – Strengthens the calf muscles
         2. Cycling – Strengthens the thigh muscles and iliopsoas (psoas major and iliacus)
         The main function of the thigh muscles is to support body weight and lift the legs, so they definitely need to be well trained. The lesser-known iliopsoas (psoas major and iliacus) also plays a role in supporting the body, but its importance is no less than that of the thigh muscles. Because if the iliopsoas becomes weak, a person may struggle to stand for long periods and is more prone to being bedridden.
         In addition to cycling, another exercise that strengthens the iliopsoas is climbing stairs. However, climbing stairs puts the full body weight on the knees, which is not suitable for the elderly. Therefore, for older adults looking to train the iliopsoas, cycling remains the most appropriate option.

         III. Using Small Slopes for Strength Training
         Recent research on strength training shows that it must engage at least 30% of your maximum muscle strength to enhance muscle power. Strength training that doesn’t reach this level may still lead to muscle weakening. So how can cycling engage 30% of your maximum muscle strength? Ans.: Experiments show that cycling up a 1.25% slope for 50 meters achieves this.

       IV. Cycling Can Make Your Blood Vessels Younger
         After exercising, blood flow speeds up, generating nitric oxide, which helps soften the muscles surrounding the blood vessels. The faster the blood flow, the more nitric oxide is produced. Experiments have found that cycling can increase blood flow speed by ten times. Therefore, those with vascular issues might consider cycling to improve their blood vessels!

       V. Expert Recommendations
       Both brisk walking and cycling are aerobic exercises that can make blood vessels younger, aid in weight loss, and prevent lifestyle-related diseases, but brisk walking is not very effective at increasing muscle strength.
       How long do you need to cycle to actually make your blood vessels younger?
       Experts recommend: 40 years old – 160 minutes per week; 50 years old – 150 minutes per week; 60 years old – 140 minutes per week.
       Those without a bike or who can’t ride can try “bike exercises” to achieve similar results:
         1. Place two tissue boxes or books on the ground and step over them back and forth for ten minutes.
         2. Sit on a chair and extend one leg at a time, doing ten reps for each leg.
         3. Stand and hold onto a chair with one hand. First, lift the outer leg straight upward, then lower it. Next, open the legs and lift them sideways. Do ten reps for each leg.
       Doing the above three exercises 3–4 times a week will produce results.