# Diabetes - sport - heart rate - insulin

Dear All;

I found this very interesting blog about how to manage diabetes ; exercise and insulin.

http://www.idea2000.org/moreinfo/docs/Diabetes_Polar_tips.html

Diabetes, Sport and Heart Rate Monitor POLAR M 52

by Petr Michalik

I would like to share with you my experience with heart rate monitor POLAR M 52. I use it as a management tool to decrease chances of hypo and hyperglycemia during different sports with different length and amount of activity. I use it for hiking, running and mountain biking.

The Heart Rate Monitor Polar M 52 is one of those, which measures energy expenditure.

Firstly, let’s talk how it works.

Figure 1. Energy sources during exercise. Source: Raija Laukkanen/Polar Electro Oy, Information about Owncal Calorie Counting Feature.

From the user’s manual: The energy expenditure measurement with Polar Heart Rate Monitor is most accurate in continuous activities such as walking, cycling and jogging. Polar Heart Rate Monitor shows the energy expenditure in kilocalories (kcal)…when you expend calories; your body actually uses fat and carbohydrates as energy resources. The amount of fat from the total calorie expenditure varies between 10% - 60%. The rest is mostly carbohydrate (See figure 1). The energy expenditure assessment is based on gender, body weight and heart rate. Figure 2 presents comparison between the distribution of energy sources in jogging and walking session. The intensity of exercise depends also on the amount of active muscle mass. Cross-country skiing and rowing typically are more intensive than walking or bicycling due to upper body muscle mass activity needed. Brisk walk expends more calories than slow walk when done for equally long time.

Figure 2. Comparison between the distribution of energy sources in jogging and walking

How it works for me. I take three Humalog shots and two Humulin N shots per day. Lets assume, that I have a lunch at noon and last insulin shot at lunchtime. After work about 6 pm I do some exercise. Of course, the assumption is, that my sugar level is in a good range (3.5 to 8.0 mmol/l = 63 to 144 mg/dl). Then of course I have to know how much I am going to run/bike/hike. ½ an hour run = 20 g of carbohydrates, an hour run = 40 g of carbohydrates. I think, everyone does it similar way, no revolutionary thoughts yet. I start running and the calorimeter starts to count. I know that for every 200 kcal consumed at certain heart range I need 10 g of carbohydrates. So if I consume over 400 kcal and I have eaten 20 g of carbohydrates and it is still 20 minutes to go home I know I should take a bite of carbs. It is quite simple example, heart monitor is not needed for that, but imagine a mountain bike trip, where you do not know how long you went up (with high consumption) and down (with lower consumption). The same goes for long duration hiking or running. Another factor that has to be taken into account is that the exercise is performed regularly, because body reacts differently at random exercise (not regular) exercise and differently after couple of weeks of exercise.

I know, there are too many assumptions and everyone is individual, specifically talking about body reaction to insulin and exercise. Please, take this as an example showing that there are different tools, which can help us.

I have used the heart monitor and it helped me to prevent hypo/hyperglycemia in following events:

• running to the top of Mount Elbert (highest peak in US Rocky Mountains from Twin Lakes (distance 6 miles/9.5 one way, elevation gain 4,933 feet/1,500 m.

• “friendly” road bike ride in Krkonose mountain, the Czech Republic (distance 135 km, elevation 3.200 m)

• Manitoba Provincial Championships Cycling Time Trial (3rd place)

• Manitoba Provincial Championships Orienteering Short “O” (2nd place)

• Manitoba Provincial Championships Orienteering Short Classic (1st place)

Source: Raija Laukkanen/Polar Electro Oy, Information about Owncal Calorie Counting Feature.

Source:

1. Polar M52ä heart rate monitor user’s manual
2. Source: Raija Laukkanen/Polar Electro Oy, Information about Owncal Calorie Counting Feature

Petr Michalik October 2000,