HIGH-DOSE EXERCISE DOES NOT INCREASE HUNGER OR ENERGY-INTAKE IN FREE-LIVING MALES

Objective: To examine the effects of a high dose (two high-intensity e xercise sessions) of exercise on energy intake (EI) and subjective sta tes (hunger and mood). Design: Using a within subjects design, there w ere two treatment conditions, each of two consecutive days. Setting: T he Human Appetite Research Unit at Leeds University Psychology Departm ent, Subjects: Eight lean males who were regular exercisers were recru ited from the student/staff population of Leeds University. Interventi ons: The effects of the high dose of exercise on Ex1 were compared wit h the effects on the day immediately after exercise (Ex2) and two cons ecutive days of no exercise (R1 and R2). EI was monitored using self-r ecord food diaries and subjective states were tracked using a new Elec tronic Appetite Rating System (EARS). Heart rate and physical activity were also measured. Results: Feelings of hunger were not elevated by the high dose of exercise on Ex1 or on the day after exercise (Ex2). I n fact, average daily feeling of hunger on Ex1 was significantly lower compared with the average daily feeling of hunger on Ex2 (t=3.15, d.f .=7, P< 0.05), but not when compared with R1 or R2. EI and macronutrie nt intakes were not different on Ex1, Ex2, R1 or R2. Therefore, there was no increase in EI on Ex1 or Ex2 to account for the measured increa se in exercise-induced energy expenditure (1200kcal). Continuously mon itored heart rate and activity profiles indicated that there was no di fference in activity during the non-exercise periods between the four days. Conclusions: This study indicates that a high dose of exercise i n one day failed to have any effect on EI within the same day or on th e day immediately after exercise, compared with days of no exercise. T hese results demonstrate that an acute but substantial increase in ene rgy expenditure GEE) due to intense exercise does not automatically in crease hunger or EI within 48 h. This indicates the absence of any str ong coupling between EE and EI in the short-term, probably as a result of food intake being held in place by environmental contingencies and short-term pre-absorptive physiological responses arising from eating itself.