A runner who finishes a marathon in 5 hours needs more carbohydrate across the race than one who finishes in 3. This is because the body is burning fuel for 2 extra hours at a pace that still relies heavily on carbohydrate. Older runners are a large part of that slower field. At the New York City Marathon, men aged 40 and over made up more than 50% of male finishers in the 2000s. Women in the same age range made up 40% of female finishers. For these runners, you need to build a fueling plan around hours on the course, starting well before the halfway mark. ShopWalking Shoes
Carbohydrate Per Hour by Race Length
Sports nutrition guidance sets intake during exercise by duration. Events of 1 to 2.5 hours call for 30 to 60 grams of carbohydrate per hour. Events longer than 2.5 hours call for up to 90 grams per hour, which requires a mix of glucose and fructose, since glucose alone is absorbed and used at about 60 grams per hour.
An older runner finishing a half marathon in 2 hours 15 minutes is in the first band. The same runner in a full marathon, out for 4 hours 45 minutes or longer, is in the second. A practical marathon starting point is 45 to 60 grams per hour, taken in portions every 20 to 30 minutes from the first half hour of the race, with higher rates reserved for runners who have built up to them in training. Most gels and chews list 20 to 25 grams of carbohydrate per serving, so 50 grams an hour is about 2 servings, and the label is the simplest way to count.
Fuel Texture and Stomach Emptying
In a recent ultrasound study of 30 adults aged 65 to 80 and 30 younger adults, the older group emptied 35% of a solid meal from the stomach in 4 hours, compared with 51% in the younger group. Liquid emptying time was the same in both groups, at a median of 45 minutes.
Because solids leave the stomach more slowly, solid fuel is better eaten early in a long race, with gels or sports drinks used in the later miles. Runners who prefer something to chew can buy energy waffles to eat in the first hour or two, alongside small amounts of banana or dried fruit from home, then move to liquid carbohydrate for the second half. Each option should be tested on a training run of at least 90 minutes before it goes into a race plan. Aid station drinks also supply carbohydrate. A sports drink at 6% carbohydrate supplies about 14 grams per 8-ounce cup, so 2 cups an hour provide close to half of a 60-gram target, and the remainder can come from what the runner carries. BookCoaching
Diabetes Medication and Long Runs
The 2020 National Diabetes Statistics Report found that 29.2% of older Americans have diabetes, counting diagnosed and undiagnosed cases in adults aged 65 and up. For runners in that group, some diabetes drugs change the fueling plan.
Exercise lowers blood glucose by raising insulin sensitivity and by letting muscle take up glucose for fuel. The American Diabetes Association lists insulin and sulfonylureas as the medications with a high risk of low blood sugar during exercise. For people using them, prolonged aerobic exercise of 30 minutes or more usually requires extra carbohydrate, a lower medication dose, or both, and the right adjustment depends on the drug and the timing of the run.
A runner in that group should work out a race-day plan with their doctor before the first long training run, and should carry a fast-acting carbohydrate source on every run regardless of the plan.
Training the Gut
A Yale analysis of about 415,000 New York City Marathon participants from 1983 to 1999 found that older runners can improve faster than younger ones, with women aged 50 to 59 cutting more than 2 minutes a year from their times. The gut also adapts. In a 28-day study of trained cyclists, a diet that supplied extra carbohydrate during daily training raised the rate at which the body used carbohydrate taken during exercise by about 16%.
For an older runner, the long run is the place to build intake step by step. A runner who starts at 30 grams per hour can add 10 to 15 grams every 2 or 3 weeks, and note any bloating or cramping at each level.
