Treadmill running reduces parathyroid hormone concentrations during recovery compared with a nonexercising control group.
BACKGROUND
Lower PTH concentrations reported in the hours after acute, endurance exercise compared with preexercise levels might be influenced by factors such as circadian fluctuations.


OBJECTIVE
The objective of the study was to compare postexercise PTH concentrations with a nonexercising control group.


METHODS
A laboratory-based study with a crossover design, comparing a 60-minute (at 10:30 am) bout of treadmill running at 65% of the maximal rate of oxygen uptake (exercise) with semirecumbent rest (CON). Blood samples were obtained immediately before (baseline 10:15 am) and after (11:30 am) exercise and during recovery (12:30 am, 1:30 pm, and 2:15 pm).


METHODS
Ten physically active men (mean ± 1 SD, age 26 ± 5 y; body mass 78.3 ± 5.8 kg; maximal rate of oxygen uptake 57.3 ± 6.9 mL/kg(-1) · min(-1)) participated in the study.


METHODS
PTH, albumin-adjusted calcium, and phosphate concentrations were measured.


RESULTS
PTH concentrations increased (+85%, P < .01) during exercise and were higher than in CON immediately at the end of exercise (4.5 ± 1.9 vs 2.6 ± 0.9 pmol/L(-1), P < .05). In the postexercise period (12:30-2:15 pm), PTH was not different compared with baseline but was lower compared with CON at 1:30 pm (-22%; P < .01) and tended to be lower at both 12:30 pm (-12%; P = .063) and 2:15 pm (-13%; P = .057). Exercise did not significantly affect the albumin-adjusted calcium concentrations, whereas phosphate was higher than CON immediately after exercise (1.47 ± 0.17 vs 1.03 ± 0.17 pmol/L(-1), P < .001) and was lower at 1:30 pm (-16%: P < .05).


CONCLUSIONS
Lower PTH concentrations after acute endurance running compared with a rested control condition suggest a true effect of exercise.
Human Sciences (J.P.R.S., A.C.), QinetiQ Ltd, Farnborough GU14 0LX, United Kingdom; Biomedical, Life, and Health Sciences Research Centre (C.S.), School of Science and Technology, Nottingham Trent University, NG1 4BU Nottingham, United Kingdom; Department of Occupational Medicine (J.P.G.), Headquarters Army Recruiting and Training Division, Upavon SN9 6BE, Wiltshire, United Kingdom; Department of Musculoskeletal Biology (J.D.), University of Liverpool, Liverpool L69 7ZX, United Kingdom; and Norwich Medical School (W.D.F.), University of East Anglia, Norwich NR4 7TJ United Kingdom.
Jonathan P R
JP
Scott
Craig
C
Sale
Julie P
JP
Greeves
Anna
A
Casey
John
J
Dutton
William D
WD
Fraser
D000328:Adult; D018592:Cross-Over Studies; D015444:Exercise / Q000502:physiology*; D006801:Humans; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology; D010281:Parathyroid Hormone / Q000097:blood*; D012420:Running / Q000502:physiology*
D010281:Parathyroid Hormone