Work-Related Effects of Heat, Activity, and Fat in Middle Aged Men

Summary

Obesity is associated with many undesirable health effects and disease, and middle age is associated with increased risk for disease. Unfortunately, while others have looked at the effects of obesity, gender, and middle age, the combined effects of obesity and middle age on men's ability to do work in hot industrial environments have not been satisfactorily investigated.

This small study evaluates the heat tolerance of lean and obese middle aged men both while exercising and resting and the ways in which each compensate for and dissipate increasing environmental heat and heat generated by the body while exercising.

As obesity is a worldwide public health crisis and as populations in many industrialized nations age, it is important to understand the combined effects of obesity and middle age for men on their ability to safely work in hot environments. Such information will permit establishing and revising of safe work standards and inform public health outreach to the target population, itself.

Conditions

• Obesity
• Gender
• Problem of Aging

Interventions

PROCEDURE

Cardiopulmonary Exercise Stress Test

Test preceded by warm-up treadmill walking 5 min at 4.8 km/h, 5% grade with a 1 min sitting rest period. Test, then, begins at 4.8 km/h, 2.5% grade with incremental grade increases every 2 min until exhaustion. Ambient environment is maintained at neutral, with effective temperature of 19-21° C. Heart, lungs, temperature, and sweating is monitored during testing.

PROCEDURE

Climatic-Controlled Cardiopulmonary Exercise Stress Test

Test includes 30 min walking bouts on the treadmill, with two 5 min sitting rest periods between bouts (Rest I and Rest II) and 15 min sitting recovery period (Rest III), in effective temperatures of 21.1 (baseline), 26.7, 29.4, 32.2, and 35.0° C. Heart, lungs, temperature, and sweating is monitored during testing.

PROCEDURE

Body Composition Evaluation

Multiple methods are used to accurately estimate percentage of body mass (weight) composed of fat, muscle, bone, and other connective tissues. Four different methods, including caliper and hydrostatic (underwater weighing) are used in this study to ensure an accurate estimation.

PROCEDURE

Pre-Exercise Risk Assessment

Includes non-invasive measurements of body functioning, a physical examination by a physician, and blood and urine testing to select subjects who can exercise with relative safety.

Sponsors & Collaborators

• Freeman-Sheldon Research Group, Inc.

  lead OTHER

Principal Investigators

• Rodger J McCormick, DEd · Freeman-Sheldon Research Group, Inc.

Eligibility

Min Age

35 Years

Max Age

55 Years

Sex

MALE

Healthy Volunteers

Yes

Timeline & Regulatory

Start

1972-06-30

Primary Completion

1972-12-31

Completion

1972-12-31

Countries

• United States

Study Locations