Clinical trial NCT01073332: The Effects of a Dietary Supplement on Exercise Performance in Healthy Older Adults"
Official title: Arginine and Antioxidant Supplement on Performance in Elderly Male Cyclists: A Randomized Controlled Trial
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Excessive Physical Exercise, Unspecified
Lead sponsor: University of California, Los Angeles
Sponsor class: OTHER
First posted: 2010-02-23
Enrollment: 16
Sex: ALL
Minimum age (years): 50
Maximum age (years): 75
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: BASIC_SCIENCE

Brief summary: Human exercise capacity decreases with aging. One explanation may be that blood vessels stiffen with age and release less of a compound called nitric oxide (NO). This compound normally relaxes blood vessels and increases blood flow to muscles, but damaging compounds called free radicals can interfere with this process. Antioxidants may help prevent free radicals from inactivating nitric oxide. The purpose of this study was to investigate the effects of an antioxidant supplement that supports NO production on exercise performance in elderly male cyclists.

Detailed description: Since the discovery of the vascular smooth muscle relaxant properties of nitric oxide (NO) over 25 years ago, studies have implicated this molecule in modulating such processes as atherosclerosis, impotence, angina, platelet function, and blood pressure, among others. Through vascular smooth muscle relaxation in both coronary and skeletal muscle arteries, as well as via independent mechanisms, nitric oxide has also been implicated in improvement of exercise capacity. In addition, NO may be involved in the immune system, assist in memory function and sleep regulation, and act as a cellular signaling messenger. Youthful, healthy and athletic individuals generally have a healthier NO system, compared to sedentary, unhealthy and aging individuals. NiteworksTM is a dietary supplement that includes L-arginine, an amino acid that acts as a nitric oxide donor and has been shown to increase levels of this molecule in the body. NiteworksTM has been formulated as a composite mixture along with other supplements, including antioxidants, that may act synergistically with L-arginine in enhancing exercise capacity.

Eligibility criteria: Inclusion Criteria:

* Males and females
* Age 50-75 years, inclusive
* Ability to perform pulmonary function and exercise tests
* Willingness to take supplement powder for 3 weeks
* Ethical: Subject must sign the Institutional Review Board-approved written informed consent prior to he initiation of any study specific procedures or randomization. A subject will be excluded for any condition that might compromise the ability to give truly informed consent for participation in the study.

Exclusion Criteria:

* Existing pulmonary or cardiovascular disease
* Previous cardiac surgery
* Not able to tolerate breathing through mouthpiece for up to 20 minutes
* Musculoskeletal disease that would limit exercise

Primary outcomes:
measure: Arginine and antioxidant supplements, as compared with placebo will improve exercise performance
timeFrame: 3 weeks
Secondary outcomes:
measure: Arginine and antioxidant Supplements improve maximal oxygen uptake and anaerobic threshold
timeFrame: 3 weeks
Other outcomes:
Locations:
city: Los Angeles
country: United States
facility: University of California, Los Angeles
state: California
Study officials:
affiliation: University of California, Los Angeles
name: Zhaoping Li, MD, PhD
role: PRINCIPAL_INVESTIGATOR
References: