Advice for Professionals

Defining Type of activity

Being able to define what type of exercise a patient is doing is key to understanding what will happen to their blood glucose when they perform that exercise.

In simple terms there are three types of activity

1.	*Flexibility exercises* - These improve the range of motion in muscles and joints. This form of exercise is recommended to be performed before and after the other forms of exercise to limit injury. Examples yoga, Tai chi.
2.	*Aerobic exercises.* These exercises use oxygen and help to improve how long you can continue to do an exercise for (cardiovascular endurance). Examples include cycling, swimming, walking, skipping rope, rowing, running, and hiking
3.	Anaerobic exercises. These exercises do not use oxygen and help to improve short-term muscle strength and anaerobic capacity. Examples include weight training, high-intensity training, or sprinting

Table 1 below compares these types of exercises.

Sometimes defining the exercise can difficult as

A.	Depending on how you are doing the exercise could change the type of exercise it is. For example if you are swimming and doing 2 lengths as fast as you can (sprints) and then having a rest and repeating this this is anaerobic exercise. In contrast if you are swimming 50 lengths without a break then this is an aerobic exercise
B.	Some sports or exercises can be a made up of a mixture of these types of exercise. Most team games are a mixture of aerobic and anaerobic

Table 2 gives examples of different types of exercise

Effect of different types of exercise on glucose

The reason for determining what type of exercise you patients is doing is that different types of exercise tend to effect glucose in a different way (see figure 1). In general, though the response to each exercise is as follows;

Flexibility exercise - glucose will tend to remain steady.

Aerobic exercise - glucose will tend to fall.

Anaerobic exercise - glucose will tend to rise.

Mixed exercise - the change in glucose will depend on the make-up of the exercise.

If more aerobic than anaerobic glucose will fall.
If more anaerobic than aerobic glucose will tend to rise.
If equal amounts of aerobic and anaerobic exercise, then glucose will remain steady.

Figure 1 - Glucose control in a person with Type 1 diabetes performing different types of exercise

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