Hiking at altitude
There is no reason why people with diabetes should not participate in activities at altitude, but there may be changes in insulin and carbohydrate needs. You will need to give the five following areas special consideration:
If you control your diabetes with insulin or other oral hypoglycaemic agents then your planned activity should take into account the following:
- If you are likely to be some distance away from insulin supplies, frequent monitoring and planning for eventualities is the most important consideration for people on trekking, mountaineering or skiing trips. Take supplies and make contingency plans.
- Work your way up the mountains slowly. Start with moderate heights - not Everest. Find out how your diabetes is affected at lower altitudes before attempting prolonged or high treks. Gradual acclimatisation will reduce the incidence of acute mountain sickness and limit the need for medications, both of which may compromise your diabetes control.
- Injection sites should be away from areas used during activity (the stomach is ideal). Keep used needles in a suitable container for eventual disposal.
- Monitor as frequently as you can and keep monitoring and insulin equipment as close to optimum temperature as possible, using shelter, bubblewrap and body-warmth in cold environments, and ‘Frio’ or equivalent during hot days. Insulin becomes ineffective if frozen or if it goes above 25 degrees centigrade. Take a back-up meter and batteries. Cold hands make testing difficult, so wear gloves before you test. If the reading does not seem in keeping with the signs or symptoms you’re experiencing, then retest, aiming for the best possible monitoring conditions. Also, test your urine for glucose as an alternative to meters, which may be unreliable at altitude.
- Signs & symptoms of hypoglycaemia: disorientation; trembling; sweating; blurred vision; extreme hunger; anxiety; pallor; rapid pulse – these may also be recognised by those around you.
- Symptoms of hyperglycaemia: thirst; excessive urination and extreme fatigue – take care as these may be dismissed as normal reactions to activity
- Fast-acting carbohydrate snacks and short-acting insulin should always be to hand. Keep supplies of food and insulin on your person: bags can be lost; things can fall out.
- Spread supplies amongst two or three people. Take more than you need whether for one day or longer if you expect to be away from your base camp for any length of time. If blood glucose levels rise, you may need short-acting insulin quickly.
- Altitude increases carbohydrate needs, whilst the cold can suppress the usual mechanisms for fat breakdown. Both these things may increase the risk of hypoglycaemia.
- Eat carbohydrate-rich breakfasts, such as cereals and toast and jam. Iron-rich foods (for example, red meats, poultry, fish and cereals fortified with iron) will increase haemoglobin (the oxygen transporter) and maximise oxygen uptake from the air. The absorption of iron can be enhanced by Vitamin C (eg by consuming fruit or fruit juice with meals). Tea can inhibit iron absorption.
- Hypoglycaemia can suppress shivering, one of the normal responses to cold, and increase the risk of hypothermia (body-core temperature lower than 35 degrees centigrade).
- The sun and/or altitude may increase fluid needs. Take adequate drinks and keep them liquid (not ice in freezing conditions) and wear a hat, sunglasses and sunscreen to prevent sunstroke.
If you have Type 2 diabetes treated by diet and activity or by metformin or glucobay alone (not treated with insulin), you are very unlikely to have a hypo. However, you may need food (particularly starchy food such as bread and potatoes) soon after you have been active.
Discuss emergency action with your team leader and members of your party beforehand. Never go off alone. Although hypoglycaemia is more common than hyperglycaemia, prompt treatment is necessary for both. Ketoacidosis (high blood-glucose levels leading to a build up of ketones) is dangerous if untreated and needs emergency treatment.