# Anabolic Versus Catabolic Skeletal Effects of Endurance or Resistance Exercise in Older Veterans

> **NIH VA IK2** · VA EASTERN COLORADO HEALTH CARE SYSTEM · 2022 · —

## Abstract

Exercise is frequently recommended to reduce the risk of osteoporotic fracture. However, bone does not
always result in the expected improvements in bone mass, and there is evidence that endurance exercise may
lead to bone loss under certain conditions. It is our contention that disruptions in calcium homeostasis during
exercise, resulting in a decrease in serum ionized calcium (iCa) and increases in parathyroid hormone (PTH)
and c-telopeptide of type I collagen (CTX; a marker of bone resorption) that occur shortly after the start of
exercise, may be responsible for the lack of the expected improvements in bone mineral density. The iCa,
PTH, and CTX responses to exercise have been well-characterized for both young and older adults in
response to a single endurance exercise bout, but it is unclear if resistance training (e.g., weightlifting) results
in the same exercise-induced disruption in calcium homeostasis. Further, it is unclear how the iCa, PTH, and
CTX response to exercise may change with exercise training, and if a bone anabolic response to exercise can
be detected after repeat exercise bouts. The bone anabolic response to exercise (assessed by procollagen of
type I terminal propeptide, P1NP; a marker of bone formation) has yet to be fully characterized, but that may
be due to the testing of single exercise bouts and the short sampling timeline following exercise. To address
these gaps in knowledge, up to 60 Veterans (30 men, 30 women), aged 60-80 years, will be randomized to 1)
stationary cycling; or 2) resistance training and will complete 10 weeks of supervised exercise training 3x/week
(30 total exercise training sessions). This number of exercise visits was due to the demonstrated increase in
P1NP after 28 doses of teriparatide, a PTH analog, that results in bone formation. During the 1st, 15th, and 30th
exercise training session, participants will undergo an acute exercise testing bout with pre- and post-exercise
sampling up to 48 hours after exercise. Blood samples will be collected to measure iCa, PTH, CTX and P1NP.
The primary aims are 1) to determine if resistance exercise results in a different bone biomarker response
compared to what we have observed during endurance exercise in older adults; 2) determine if resistance
and/or endurance exercise result in an increase in P1NP over 10 weeks of exercise training. Exploratory
outcomes related to changes in fitness and functional status will address how Veteran health is impacted by
each exercise type, which will be used to inform future applications. The biomarker and functional outcomes
information are the next step in determining the appropriate “dose” of exercise, consisting of factors such as
exercise type, frequency, duration, and intensity (which will be explored in future research), can be used to
enhance Veteran health. Exercise should continue to be recommended for overall health, but future
interventions could incorporate what is known about the dose of exercise that is n...

## Key facts

- **NIH application ID:** 10420843
- **Project number:** 1IK2RX003820-01A1
- **Recipient organization:** VA EASTERN COLORADO HEALTH CARE SYSTEM
- **Principal Investigator:** Sarah J Wherry
- **Activity code:** IK2 (R01, R21, SBIR, etc.)
- **Funding institute:** VA
- **Fiscal year:** 2022
- **Award amount:** —
- **Award type:** 1
- **Project period:** 2022-04-01 → 2027-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10420843

## Citation

> US National Institutes of Health, RePORTER application 10420843, Anabolic Versus Catabolic Skeletal Effects of Endurance or Resistance Exercise in Older Veterans (1IK2RX003820-01A1). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10420843. Licensed CC0.

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