NCT07344636

Brief Summary

Zone 2 training, a low-intensity endurance exercise performed at approximately 66-80% of VO₂max or near the first ventilatory threshold, has gained popularity for improving aerobic capacity, fat metabolism, and mitochondrial efficiency. It preserves glycogen stores and delays fatigue, making it an essential training method for both athletes and recreational exercisers. Nicotinamide adenine dinucleotide (NAD) is a vital metabolite that regulates cellular energy metabolism and redox homeostasis. It participates in oxidative reactions within the tricarboxylic acid cycle and electron transport chain, sustaining ATP synthesis and mitochondrial efficiency. Exercise influences multiple pathways of NAD metabolism, altering the NAD⁺/NADH ratio and thereby affecting energy production and fatigue resistance. Studies have shown that both aerobic exercise and NAD precursor supplementation (e.g., nicotinamide riboside \[NR\]) can elevate body NAD levels and enhance mitochondrial function, though findings remain inconsistent due to variations in dosage and participants' characteristics. This study aims to investigate how acute NR supplementation interacts with Zone 2 cycling training in adults. Specifically, it examines the temporal and dose-dependent effects of NR supplementation on metabolic flexibility and exercise performance. The results may clarify the potential synergistic benefits of combining NAD supplementation with low-intensity endurance training to improve aerobic adaptability.

Trial Health

77
On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
16

participants targeted

Target at below P25 for not_applicable

Timeline
13mo left

Started Jan 2026

Geographic Reach
1 country

1 active site

Status
recruiting

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

Click on a node to explore related trials.

Study Timeline

Key milestones and dates

Study Progress30%
Jan 2026Jul 2027

First Submitted

Initial submission to the registry

January 5, 2026

Completed
1 day until next milestone

Study Start

First participant enrolled

January 6, 2026

Completed
9 days until next milestone

First Posted

Study publicly available on registry

January 15, 2026

Completed
1.5 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

July 1, 2027

Expected
Same day until next milestone

Study Completion

Last participant's last visit for all outcomes

July 1, 2027

Last Updated

March 18, 2026

Status Verified

March 1, 2026

Enrollment Period

1.5 years

First QC Date

January 5, 2026

Last Update Submit

March 16, 2026

Conditions

Health Adult Subjects

Outcome Measures

Primary Outcomes (1)

  • Substrate utilization (CHO and fat oxidation rate)

    From enrollment to the end of treatment at 4 weeks

Secondary Outcomes (9)

  • Oxygen consumption

    From enrollment to the end of treatment at 4 weeks

  • Heart rate

    From enrollment to the end of treatment at 4 weeks

  • Blood glucose concentration

    From enrollment to the end of treatment at 4 weeks

  • Blood lactate concentration

    From enrollment to the end of treatment at 4 weeks

  • Peak power output

    From enrollment to the end of treatment at 4 weeks

  • +4 more secondary outcomes

Other Outcomes (5)

  • Height

    From enrollment to the end of treatment at 4 weeks

  • Weight

    From enrollment to the end of treatment at 4 weeks

  • Power output at VT1

    From enrollment to the end of treatment at 4 weeks

  • +2 more other outcomes

Study Arms (3)

600 mg

EXPERIMENTAL
Dietary Supplement: Nicotinamide Riboside (NR)

300 mg

EXPERIMENTAL
Dietary Supplement: Nicotinamide Riboside (NR)

0 mg

NO INTERVENTION

Interventions

Nicotinamide Riboside (NR)DIETARY_SUPPLEMENT

600 mg NR

600 mg

Eligibility Criteria

Age18 Years - 80 Years
Sexall
Healthy VolunteersYes
Age GroupsAdult (18-64), Older Adult (65+)

You may qualify if:

  • Over 18 years old
  • BMI \<30 kg/m2

You may not qualify if:

  • Present of health conditions that contraindicate participation in exercise training, such as a history of cardiovascular disease, cancer, or musculoskeletal disorders
  • Currently taking vitamin B supplements and/or NAD precursors
  • Taking medication that may affect the test results

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (1)

G02, Kwok Sports Building, The Chinese University of Hong Kong

Hong Kong, Please Select, 999077, China

RECRUITING

MeSH Terms

Interventions

nicotinamide-beta-riboside

Study Design

Study Type
interventional
Phase
not applicable
Allocation
RANDOMIZED
Masking
DOUBLE
Who Masked
PARTICIPANT, OUTCOMES ASSESSOR
Purpose
OTHER
Intervention Model
CROSSOVER
Sponsor Type
OTHER
Responsible Party
SPONSOR INVESTIGATOR
PI Title
Principal Investigator

Study Record Dates

First Submitted

January 5, 2026

First Posted

January 15, 2026

Study Start

January 6, 2026

Primary Completion (Estimated)

July 1, 2027

Study Completion (Estimated)

July 1, 2027

Last Updated

March 18, 2026

Record last verified: 2026-03

Locations

CN(1)