Inability to match energy intake with energy expenditure at sustained near-maximal rates of energy expenditure in older men during a 14-d cycling expedition.
BACKGROUND
The upper rates of energy expenditure (EE) and the corresponding regulation of energy intake (EI), as described in younger trained subjects, are not well elucidated in older subjects.


OBJECTIVE
The aim was to investigate EE in older men during prolonged cycling and determine whether it is sufficiently matched by EI to maintain energy balance. In addition, we investigated appetite ratings and concentrations of appetite-regulating hormones.


METHODS
Six men (mean ± SE age: 61 ± 3 y) completed 2706 km of cycling, from Copenhagen to Nordkapp, in 14 d. EE was measured by using doubly labeled water, and food and drink intake was recorded by the accompanying scientific staff. Energy balance was calculated as the discrepancy between EI and EE and from changes in body energy stores as derived from deuterium dilution. Fasting hormones were measured before and after cycling, and appetite ratings were recorded twice daily.


RESULTS
EE (±SE) increased from 17 ± 1 MJ/d before to 30 ± 2 MJ/d during the cycling trip (P < 0.001), which is equivalent to 4.0 ± 0.1 times the basal metabolic rate. Although body weight remained stable during the 14 d of cycling, body fat decreased (-2.2 ± 0.7 kg; P = 0.02) and fat-free mass increased (2.5 ± 0.6 kg; P = 0.01). EI was 25 ± 1 MJ/d during cycling, resulting in a negative energy balance calculated by the EE - EI gap (-5.2 ± 1.2 MJ/d). Calculated from changes in body energy stores, energy balance was also negative (-4.8 ± 2.0 MJ/d) during the first week. In the morning and evening, hunger ratings increased (both P = 0.02), whereas ratings of fullness decreased in the evening (P = 0.04). Fasting plasma concentrations of insulin increased by 120% ± 15% (P = 0.02), glucagon-like peptide 1 (GLP-1) by 60% ± 20% (P < 0.01), and Polypeptide YY(3-36) by 80% ± 30% (P < 0.02) after cycling.


CONCLUSIONS
Older male cyclists sustained near-maximal rates of EE during prolonged cycling but were unable to upregulate EI to maintain energy balance. Despite the presence of increased motivation to eat, a more profound counteracting physiologic stimulus inhibiting increases in EI was present. This trial was registered at clinicaltrials.gov as NCT02353624.
Department of Biomedical Sciences, madsrl@sund.ku.dk.
Mads
http://orcid.org/0000-0003-2060-308X
M
Rosenkilde
Department of Biomedical Sciences, Center of Healthy Aging.
Thomas
T
Morville
Department of Biomedical Sciences, Center of Healthy Aging.
Peter Riis
http://orcid.org/0000-0002-8175-5514
PR
Andersen
Department of Biomedical Sciences, Center of Healthy Aging.
Katja
K
Kjær
Institute of Sports Medicine Copenhagen, Bispebjerg Hospital, Copenhagen, Denmark; and.
Hanne
H
Rasmusen
Department of Biomedical Sciences, Novo Nordisk Foundation Center for Basic Metabolic Research, and.
Jens Juul
JJ
Holst
Department of Biomedical Sciences, Center of Healthy Aging.
Flemming
F
Dela
Department of Human Biology, Maastricht University, Maastricht, Netherlands.
Klaas
K
Westerterp
Department of Nutrition, Exercise, and Sports, University of Copenhagen, Copenhagen, Denmark;
Anders
A
Sjödin
Department of Biomedical Sciences, Center of Healthy Aging.
Jørn W
http://orcid.org/0000-0001-9724-5423
JW
Helge
D015502:Absorptiometry, Photon; D001069:Appetite Regulation; D001642:Bicycling; D001823:Body Composition; D058620:Elder Nutritional Physiological Phenomena; D002149:Energy Intake; D004734:Energy Metabolism; D052216:Glucagon-Like Peptide 1 / Q000097:blood; D006339:Heart Rate; D006801:Humans; D007328:Insulin / Q000097:blood; D008297:Male; D008875:Middle Aged; D018670:Monitoring, Ambulatory; D010101:Oxygen Consumption; D010446:Peptide Fragments / Q000097:blood; D019894:Peptide YY / Q000097:blood; D005082:Physical Exertion; D064133:Sports Nutritional Physiological Phenomena; D015854:Up-Regulation
D007328:Insulin; D010446:Peptide Fragments; D019894:Peptide YY; C061785:peptide YY (3-36); D052216:Glucagon-Like Peptide 1
appetite; energy balance; energy expenditure; energy intake; exercise