I am spotlighting two very unique articles in this month’s issue of MSSE: one concerning older firefighters and their response to heat exposure, and the other on the metabolic/cardiovascular risk profiles of overweight/class I obese individuals with a high strength fitness index.
Firefighting is one of the most physically demanding occupations, requiring a high level of fitness and superior tolerance to heat. However, as in many industries, the number of older firefighters is rapidly increasing, raising many health and safety concerns. In addition to the age-related reductions in physical capacity, aging is associated with marked impairments in the body’s ability to dissipate heat. While older firefighters often believe that they are more heat resilient, and are therefore at a reduced risk of heat injuries due to their regular exposure to heat, a study by Kenny et al. reported in this month’s journal shows that, in fact, older firefighters experience marked reductions in their capacity to dissipate heat relative to their younger firefighting counterparts, and the level of thermoregulatory impairment is comparable to that observed in their age-matched counterparts from the general population. Such changes may have important repercussions for the health and safety of those who remain on active firefighting duty until mandatory retirement. As a complement to this paper, I refer you to the paper of Ruby et al. [Total energy expenditure during arduous wildfire suppression. Med Sci Sports Exerc. 2002;34(6):1048-1054].
Obesity is prevalent in the U.S., and is of course associated with numerous health risks including type 2 diabetes, cardiovascular disease, and fatty liver disease. However, high levels of fitness reduce this association. In this month’s journal, Roberts et al. took an interesting approach to this topic. In a cross-sectional study of young men (N = 90), they found that overweight/class I obese and normal-weight individuals who are strength-trained exhibit remarkably similar cardiovascular and metabolic phenotypes, with both being healthier than untrained overweight/class I obese persons. This new evidence challenges the existing view of the importance of body weight classification per se for health risk prediction, and suggests that strength fitness may be more critical to metabolic and cardiovascular health than previously thought. Furthermore, strength fitness may be an alternate therapeutic target for those unable to normalize body weight. As a companion paper, I refer you to the highly cited paper of Jurca et al. [Association of muscular strength with incidence of metabolic syndrome in men. Med Sci Sports Exerc. 2005;37(11):1849-1855].
L. Bruce Gladden