Exercise Fatiguability in Older Adults: The Protective Effects of Dietary Nitrate Supplementation

Not Applicable

• Conditions: Aging
• Interventions: Other: Placebo Beetroot Juice; Dietary Supplement: Beetroot Juice

• Registration Number: NCT05313490
• Lead Sponsor: Marquette University

Brief Summary

Vascular and skeletal muscle function decline with age and are associated with decreased nitric oxide (NO) bioavailability. Dietary nitrate supplementation in the form of beet root juice increases NO bioavailability and improves exercise tolerance in younger adults, yet its effects on fatigability in older adults are largely unknown. The proposed research will investigate the impact of increased NO bioavailability on vascular function, skeletal muscle bioenergetics, and fatigability in older (≥65 yrs) men and women.

Detailed Description

Not available

Study Timeline

• Study First Submitted: 2022-02-14
• Study First Submitted QC: 2022-03-28
• Study First Posted: 2022-04-06
• Study Start: 2022-05-01
• Status Verified: 2022-08
• Last Update Submitted: 2022-08-22
• Last Update Posted: 2022-08-24
• Primary Completion: 2023-12-31
• Study Completion: 2023-12-31

Recruitment & Eligibility

• Status: UNKNOWN
• Sex: All
• Target Recruitment: 40

Inclusion Criteria

• Healthy men and women ≥ 60 years old

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Exclusion Criteria

1. body mass index ≥40 kg/m2;
2. type 1 or type 2 diabetes or HbA1c >6.5%
3. uncontrolled hypertension;
4. active cancer, cancer in remission, or having received treatment for any form of cancer in the previous five years;
5. coronary artery disease;
6. cardiovascular disease (e.g., PAD, PVD);
7. abnormal and untreated thyroid function;
8. chronic and/or regular nonsteroidal anti-inflammatory drugs (NSAID) consumption,
9. tobacco use (includes smoking);
10. any condition that presents a limitation to exercise (e.g., severe arthritis, COPD, neuromuscular disorder, moderate or severe cognitive impairment, Alzheimer's Disease, severe untreated sleep apnea).

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Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Placebo Beetroot Juice	Placebo Beetroot Juice	The subject will ingest 140mL of a placebo (nitrate-depleted) beetroot juice each day for 7 consecutive days.
Beetroot Juice	Beetroot Juice	The subject will ingest 140mL of a nitrate-rich beetroot juice each day for 7 consecutive days.

Primary Outcome Measures

Name	Time	Method
Change in fatigability of the knee extensor muscles with beetroot juice supplementation	Day 8 (after 7 days of placebo supplementation) and day 29 (after 14 days of a washout period with no supplementation plus 7 days of beetroot juice supplementation)	Fatigability will be quantified as the reduction in limb muscle power output during a 4-minute dynamic fatiguing exercise task using a dynamometer. Fatigability after 7 days of beetroot juice supplementation will be compared with fatigability after 7 days of placebo supplementation, with the outcome measure being the change (or difference) between these two supplementation conditions.

Secondary Outcome Measures

Name	Time	Method
Change in muscle efficiency with beetroot juice supplementation	Day 8 (after 7 days of placebo supplementation) and day 29 (after 14 days of a washout period with no supplementation plus 7 days of beetroot juice supplementation)	Muscle efficiency will be quantified as the ATP cost of contraction using phosphorus magnetic resonance spectroscopy (P-MRS). Muscle efficiency after 7 days of beetroot juice supplementation will be compared with muscle efficiency after 7 days of placebo supplementation, with the outcome measure being the change (or difference) between these two supplementation conditions.
Change in femoral artery blood flow with beetroot juice supplementation	Day 8 (after 7 days of placebo supplementation) and day 29 (after 14 days of a washout period with no supplementation plus 7 days of beetroot juice supplementation)	Femoral artery blood flow will be quantified as the change in femoral artery blood flow during a 4-minute dynamic fatiguing exercise task using a ultrasonography. Femoral artery blood flow after 7 days of beetroot juice supplementation will be compared with Femoral artery blood flow after 7 days of placebo supplementation, with the outcome measure being the change (or difference) between these two supplementation conditions.

Trial Locations

Locations (1)

Marquette University; 🇺🇸 Milwaukee, Wisconsin, United States