Maximal exercise transiently disrupts hormonal secretory patterns in standardbred geldings.
Abstract: Basal concentrations of cortisol (CORT), beta-endorphin (beta EP), growth hormone (GH) and testosterone (T) and their disruption during 32 h of recovery after treadmill exercise were investigated in 4 geldings. Blood samples were collected from resting horses every 20 min between 0600-1000 and 1500-1900 h, and hourly between 1000-1500 h on 3 consecutive days. Treadmill exercise tests comprising 2 min intervals at 30, 50, and 70% VO2max then to fatigue at 100% VO2max were conducted between 1020-1130 h on Day 2. Blood was collected before, during and 15, 30, 60 and 90 min after exercise. Mean (Cav), peak (Cmax) and total (i.e. integrated) (Ctot) concentrations were calculated for CORT, beta EP and GH during the 20 min sampling sessions, and for CORT, beta EP, GH and T between 1000-1300 h on Days 1-3 (incorporating the samples during exercise on Day 2) and 1300-1900 h on Days 1-3. Cav, Cmax and Ctot for CORT, beta EP, GH and T were greater during exercise and recovery than in the same period on Day 1. Cav and Ctot values for plasma T during the 1300-1900 h period were significantly elevated on Day 2 and compared to Day 1 (P < 0.05), but there were no differences between Days 1 and 3 values for these variables. We concluded that plasma T concentration increases in response to maximal exercise in geldings, as does plasma CORT, beta EP and GH. Furthermore, maximal exercise disrupts basal plasma concentrations of CORT, beta EP and GH for up to 24 h and T for 26-32 h post exercise in geldings, therefore reflecting the minimum recovery periods required before evaluating normal, resting levels of these hormones in horses undergoing training.
Publication Date: 2000-02-05 PubMed ID: 10659322DOI: 10.1111/j.2042-3306.1999.tb05288.xGoogle Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research investigates how intense exercise affects the hormone levels in standardbred geldings (male horses) during a 32-hour recovery period. The study found that maximal exercise disrupts normal hormone levels, including testosterone, for up to 26-32 hours after exercise.
Methodology
- The study involved 4 geldings and observed their basal concentrations of cortisol (CORT), beta-endorphin (beta EP), growth hormone (GH) and testosterone (T).
- Blood samples were taken from the horses when at rest every 20 minutes between 06:00-10:00 and 15:00-19:00 hours, and hourly between 10:00-15:00 hours for 3 consecutive days.
- The horses underwent treadmill exercise tests on the second day, with intervals at 30%, 50%, and 70% VO2max, and then until fatigue at 100% VO2max. The exercise session took place between 10:20-11:30 h.
- Blood was collected before, during, and 15, 30, 60, and 90 minutes after the exercise.
Results
- The hormone concentrations during and after the exercise were higher compared to the same period on the first day.
- The concentration levels for testosterone showed a significant increase on the second day compared to the first day.
- However, there were no differences in the testosterone levels between the first and third day.
- According to the results, plasma T concentration increases in response to maximal exercise in geldings, as does plasma CORT, beta EP, and GH.
- The study concluded that intense exercise disrupts the normal hormone levels in geldings for up to 24 hours for CORT, beta EP and GH, and 26-32 hours post exercise for T.
Implications
- The findings from this study suggest that these are the minimum recovery periods required before evaluating normal, resting levels of these hormones in horses undergoing training. This could have significant implications for training and recovery schedules for horses engaged in intense exercise or competitive events.
Cite This Article
APA
Golland LC, Evans DL, Stone GM, Tyler-McGowan CM, Hodgson DR, Rose RJ.
(2000).
Maximal exercise transiently disrupts hormonal secretory patterns in standardbred geldings.
Equine Vet J Suppl(30), 581-585.
https://doi.org/10.1111/j.2042-3306.1999.tb05288.x Publication
Researcher Affiliations
- Department of Animal Science, University of Sydney, NSW, Australia.
MeSH Terms
- Animals
- Exercise Test / veterinary
- Growth Hormone / blood
- Hormones / blood
- Horses / blood
- Hydrocortisone / blood
- Male
- Oxygen Consumption
- Physical Conditioning, Animal
- Testosterone / blood
- beta-Endorphin / blood
Citations
This article has been cited 4 times.- Topczewska J, Krupa W, Sokołowicz Z, Lechowska J. Does Experience Make Hucul Horses More Resistant to Stress? A Pilot Study.. Animals (Basel) 2021 Nov 24;11(12).
- Ferlazzo A, Cravana C, Fazio E, Medica P. The different hormonal system during exercise stress coping in horses.. Vet World 2020 May;13(5):847-859.
- Shokraviyan M, Miladi-Gorji H, Vaezi GH. Voluntary and forced exercises prevent the development of tolerance to analgesic effects of morphine in rats.. Iran J Basic Med Sci 2014;17(4):271-7.
- Smith MA, Yancey DL. Sensitivity to the effects of opioids in rats with free access to exercise wheels: mu-opioid tolerance and physical dependence.. Psychopharmacology (Berl) 2003 Aug;168(4):426-34.
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