Obesity
Conditions
Keywords
Fasted exercise, Energy intake, Energy balance, Appetite, Exercise performance
Brief summary
This study will compare the appetite, energy intake, and exercise performance responses to a bout of exercise completed in the evening after an extended period of fasting with a similar bout of exercise completed in the evening and the morning, after consuming a carbohydrate-containing meal.
Detailed description
Regular exercise is known to be a successful strategy for improving several facets of health and maintaining body weight. However, many people are not engaging in enough exercise, and some may not be achieving maximum benefits from the exercise that they already do. Performing exercise in the overnight fasted state has been shown to reduce energy intake over the course of a single day, without any compensatory reductions in free-living energy expenditure. Despite these promising findings, it is likely that not every member of the population is logistically able to perform exercise in the morning due to various work, family and social commitments, and exercise in the evening may be a logical alternative for these individuals. Whether the beneficial effects of overnight fasted exercise can be observed at an alternative time of the day (i.e. the evening) is unknown. Therefore, the investigators are interested in examining the compensatory appetite and energy intake responses following a bout of evening exercise performed after an extended (7 hour) period of fasting. Exercise performance will also be assessed as a marker of voluntary energy expenditure, which if reduced, has the potential to compensate for the reduced energy balance induced by fasted exercise.
Interventions
BEHAVIORALFasted Evening Exercise
A 45 minute exercise session will take place on a stationary cycle ergometer at 18:30, after a 7-hour period of fasting. This will consist of 30 minutes of steady state cycling at 60% of VO2max, followed by an exercise test during which participants will complete as much work as they can within 15 minutes.
BEHAVIORALFed Evening Exercise
A 45 minute exercise session will take place on a stationary cycle ergometer at 18:30, after having consumed a carbohydrate-containing meal (20% estimated energy requirements) 2 hours prior. This will consist of 30 minutes of steady state cycling at 60% of VO2max, followed by an exercise test during which participants will complete as much work as they can within 15 minutes.
BEHAVIORALFed Morning Exercise
A 45 minute exercise session will take place on a stationary cycle ergometer at 10:30, after having consumed a carbohydrate-containing meal (20% estimated energy requirements) 2 hours prior. This will consist of 30 minutes of steady state cycling at 60% of VO2max, followed by an exercise test during which participants will complete as much work as they can within 15 minutes.
Sponsors
Loughborough University
Nottingham Trent University
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
NONE
Intervention model description
The study design is a randomised, controlled, crossover design in which participants undertake three exercise conditions in a randomised order with at least a seven day period in between trials.
Eligibility
Sex/Gender
ALL
Age
18 Years to 40 Years
Healthy volunteers
Yes
Inclusion criteria
* Non-smokers. * Have maintained a stable weight for 6 months (self-reported). * No history of gastric, digestive, cardiovascular or renal disease (self-reported). * Female specific: must be using a monophasic, low dose combined OCP (containing less than 50μg oestradiol and a synthetic progestin) OR females with regular menstrual cycles (self-reported).
Exclusion criteria
* Have an unusual eating pattern (i.e., extended fasting periods \>8h other than overnight - self-reported). * Severe food allergies, dislike or intolerance of study foods or drinks. * Currently undergoing a lifestyle intervention (structured diet or exercise) * Diagnosis of a condition or currently undergoing treatment therapy known to affect glucose or lipid metabolism (e.g., type-2 diabetes, taking statins), or contraindications to exercise. * Use of medication or supplements that may affect hormone concentrations. * Excessive alcohol consumption (\>14 units/week). * Intensive training schedule (\>10 hours/week). * Having received a positive COVID-19 test in the 6-month period prior to participation. * Female specific: currently pregnant or breastfeeding, the use of any hormonal contraception, and the self-reporting of short (\<24 d), long (\>35 d), or irregular menstrual cycles.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Voluntary energy intake (Kilocalories) at a laboratory-based test meal | 15 minutes following the end of the exercise session. | A laboratory-based meal consisting of pasta, tomato sauce and olive oil will be provided to participants in excess of expected consumption. Participants will be permitted 20 minutes to eat as much or as little as they desire, until 'comfortably full and satisfied'. |
| Exercise Performance (Voluntary Energy Expenditure) | Within the 15-minute performance test component of the exercise session. | Maximum energy expenditure (Kilojoules) that can be completed within 15 minutes on a stationary bicycle ergometer. The participant will be able to alter their power output by selecting up or down on the ergometer control unit as they please. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Rating of Perceived Exertion (RPE). | Within the 45-minute exercise session. | RPE will be measured at 5-minute intervals throughout the 45-minute exercise period (30 min steady state; 15 min performance test) on a 6-20 RPE scale. The participant will point to the value that corresponds to their current perceived exertion (6 being no exertion at all; 20 being maximal exertion). |
| Visual Analogue Scale for Subjective Ratings of Appetite | Baseline, 2 hours, 3 hours, 3.5 hours, 5 hours, 7 hours, 8 hours, 10 hours, 11 hours, 12 hours, 14 hours, and 24 hours. | Time-course of subjective ratings of hunger between breakfast provision and one hour after consuming lunch, measured using an appetite visual analogue scale. The scale is divided into subscales of different appetite perceptions including: hunger, fullness, desire to eat and prospective food consumption. Each subscale is rated on a 100mm scale (i.e. from 0 - 100), with a rating of 100 fully supporting the perception and a rating of 0 fully opposing the perception. |
| Pre-exercise Subjective Feelings | Immediately before the exercise session. | A single questionnaire to assess pre-exercise subjective feelings will be measured using a visual analogue scale. The scale is divided into subscales of different feelings including: motivation, readiness, tiredness, nausea, and energetic. Each subscale is rated on a 100mm scale (i.e. from 0 - 100), with a rating of 100 fully supporting the perception and a rating of 0 fully opposing the perception. |
| Enjoyment of the Exercise Bout | Immediately following the end of the exercise session. | A shortened version of The Physical Activity Enjoyment Scale (PACES) will be completed to gauge enjoyment of the exercise sessions. A scale from 1-7 will be used for eight feelings. The participant will circle the value that corresponds to which (6 being no exertion at all; 20 being maximal exertion). The scale is divided into bipolar subscales of different feelings including: enjoyment, liking, pleasure, fun, pleasantness, interest, engagement and task absorption . Each subscale is rated on a 1-7 bipolar scale (i.e. from 1 - 7), with a rating of 1 fully supporting the feeling on the left-hand side of the subscale, and a rating of 7 fully supporting the feeling on the right-hand side of the subscale. For three subscales, a positive feeling is placed at 7, and for four subscales, a negative feeling is placed at 7 (reverse scored). |
| Substrate Utilisation During Steady State Exercise. | Within the 30-minute steady-state component of the exercise session. | Measurements of VO2 and VCO2 during a 30 minute steady state bout of cycling which precedes the 15-minute performance test. |
Countries
United Kingdom
Outcome results
None listed