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NCT Number: NCT06983730

The Kidney's Response to Exercise in Heat, and the Impact of Vitamin B3 on This Response

The goal of this clinical trial is to learn about the processes occurring in the kidneys while under heat stress in healthy volunteers. The main questions it aims to answer are:

* How do the chemicals produced by the body change under conditions of higher versus lower heat stress? * What role does a specific area of the body's metabolism, known as NAD+ metabolism, play in the body's response to heat stress, and can this response be modified by taking vitamin B3?

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Key information

Conditions

Heat Strain Healthy Volunteer Study Kidney Dysfunction

Age range

18 year–45 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Early Phase 1

Primary location

Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States

Loading trial locations.

About this study

To answer these questions, researchers will compare the chemical changes in each participant under progressively higher levels of heat stress, and while taking either vitamin B3 or a placebo.

This clinical trial will occur in two stages. Participants may choose participate in stage 1 only, stage 2 only, or both parts of this clinical trial.

During stage 1, participants will exercise using a stationary rowing ergometer in a hot and humid environmental chamber for three sessions, each session separated by about a week.

  • Each session, they will be asked to work out at a progressively higher intensity with climate conditions kept the same in the chamber.
  • More intense exercise produces greater heat stress, resulting in lower, moderate, and higher levels of heat stress exposure across the three sessions.
  • Researchers will see how chemicals in the blood and urine, along with physical measurements like heart rate and body temperature, change across these different levels of heat stress.

During stage 2, participants will exercise using the same rowing ergometer in the same environmental chamber. They will do this for two sessions, each separated by about a week.

  • One of the sessions each participant will take vitamin B3, and the other session each participant will take placebo.
  • Heat stress exposure will be the same each session.
  • Researchers will again see how chemicals in the blood and urine, along with physical measurements like heart rate and body temperature, differ between sessions with vitamin B3 and sessions with placebo

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Healthy volunteer
  • Any race
  • Estimated glomerular filtration rate greater than 90 ml/min/1.73m2
  • Urine albumin/creatinine ratio less than 30mg/g
  • Nonsmoker
  • No regular dietary supplements, particularly vitamin B3
  • Physically fit, defined as having a VO2 max of between 35 and 60mL/kg/min

Exclusion criteria

  • Medical condition preventing safe participation in exercise during heat
  • Allergy to Vitamin B3
  • Severe food allergies or dietary restrictions that would preclude eating the planned study diet without major modifications

Treatment and study plan

Vitamin B3

Dietary Supplement

1000mg once a day orally for two days, once the day before the exercise session, and once the day of the exercise session.

Other names: niacinamide

Primary outcomes

  1. Urinary neutrophil gelatinase-associated lipocalin

    Time frame: Pre- and immediately post- heat stress exposure

    Marker of stress and injury in the kidney

  2. Urinary TIMP2 (tissue inhibitor of metalloproteinase-2) and IGFBP7 (insulin-like growth factor-binding protein 7)

    Time frame: Pre- and immediately post- heat stress exposure

    Marker of kidney stress and injury

Secondary outcomes

  1. Urine Quinolinate to Tryptophan Ratio

    Time frame: Pre- and immediately post- heat stress exposure

    Ratio of quinolinate to tryptophan in the urine

  2. Serum creatinine

    Time frame: Pre- and immediately post- heat stress exposure

    Marker of kidney function

Other outcomes

  1. Urine and serum metabolites, including metabolites related to nicotinamide adenine dinucleotide (NAD+)

    Time frame: Pre-, during, immediately post, and 24 hours post- heat stress exposure

    Other chemical byproducts of metabolism and exposure that may change during or impact the effect of heat stress, measured using mass spectrometry

  2. Urine and serum nicotinamide levels

    Time frame: Pre-, during, immediately post, and 24 hours post- heat stress exposure

    Levels of the interventional supplement, vitamin B3 (nicotinamide)

Study contacts

Contact information is provided by the study sponsor or research team.

Nathan H Raines, MD MPH

CONTACT

[email protected]

703-927-0992

Sponsors and collaborators

Lead sponsor

Beth Israel Deaconess Medical Center

Other

Collaborators

  • Boston University Charles River Campus
  • National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Registry information

Official study title

Development of a Clinical Experimental Heat Stress Protocol and Exploration of the Effect of Niacinamide on Physiologic, Metabolic, and Biochemical Responses to Heat Stress

Important dates

Study start
2026
Primary completion
2028
Study completion
2028
First posted
May 21, 2025
Registry last updated
Feb 5, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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