Biomedical subjects

W D Hiller

Publications and source records attributed to W D Hiller.

21 records · Page 2Linked to original sources

PubMed1986

Left ventricular structure and function by echocardiography in ultraendurance athletes.

To determine left ventricular (LV) structural and functional changes induced by ultraendurance exercise training, M-mode LV echograms and Doppler recordings of LV inflow velocity in 26 triathletes and 17 normal subjects were studied. All triathletes trained 20 to 40 hours/week in swimming, cycling and running for more than 2 years. Structurally, triathletes had normal LV systolic and diastolic cavity dimensions, but increased wall thickness (1.05 +/- 0.26 vs 0.80 +/- 0.27 cm in normal subjects, p less than 0.001), increased relative wall thickness, or h/R ratio (0.41 +/- 0.10 cm vs 0.33 +/- 0.11 cm in normal subjects, p less than 0.001), and increased LV mass (226 +/- 60 vs 143 +/- 54 g in normal subjects, p less than 0.001). LV mass correlated closely with mean exercise blood pressure during an 8-hour exercise test in 14 triathletes (r = 0.88). Systolic function at rest was similar in both groups, with no differences in fractional shortening or end-systolic stress. Diastolic LV function measured by digitized M-mode echo was similar in normal subjects and triathletes, with no differences in peak rates of cavity enlargement and wall thinning by echocardiogram. In contrast, the Doppler-derived ratio of early-to-late LV inflow velocities was slightly increased in triathletes (p less than 0.05). It is concluded that ultraendurance training produces a physiologic pattern of moderate pressure overload LV hypertrophy, in proportion to the hemodynamic load imposed during prolonged exercise. Unlike the abnormal hypertrophy of systemic hypertension, early diastolic function remains normal in the triathlete heart.

Adult↗

PubMedDate not supplied

Medical and physiological considerations in triathlons.

Triathlons (races involving consecutive swimming, bicycling, and running) have become commonplace in the United States. These races may involve from 30 minutes to 36 hours of continuous exercise, usually in warm or hot environments. Little has been published regarding the medical and physiological aspects of these events. This paper represents the first large study to date on the subject, including both an analysis of medical complications at six triathlons as well as a prospective electrolyte study conducted at two of these races. Medical records were kept and examined for all athletes requiring treatment during a typical United States Triathlon Series (USTS) race in 1986 (1,000 starters; finish times, 2 to 4 hours), a typical Ironman Qualifier (IQ) race in 1986 (622 starters; finish times, 4 to 8 hours), and the 1982 through 1985 Hawaii Ironman World Championships (4,583 starters; finish times, 9 to 17 hours). At the USTS race, fewer than 2% (17/1,000) of the starters required aid, at the IQ, approximately 10% (61/622) of the starters were treated, and at the Ironman, an average of 17% (794/4,583) received medical attention. The most common diagnoses at the USTS and IQ were dehydration and heat exhaustion. At the Ironman, dehydration and heat problems were complicated by hyponatremia. Because hyponatremia has been reported as a complication of ultraendurance events, a prospective study was performed on 36 athletes during a USTS race and 64 athletes at the 1984 Ironman race. Prerace and postrace blood samples showed that no athletes were hyponatremic following the shorter USTS race, but 27% (17/64) of the athletes studied were hyponatremic following the Ironman race.(ABSTRACT TRUNCATED AT 250 WORDS)

Athletic Injuries↗

PubMedDate not supplied

Overuse injuries in ultraendurance triathletes.

Overuse injuries represent the largest percentage of sports-related injuries requiring medical treatment. These injuries represent a substantial health issue for the millions of adults who have made physical activity an integral part of their lifestyle, but may be even more important to those pursuing ultraendurance exercise. The purposes of this study were to report the type and incidence of overuse injuries in ultraendurance triathletes and to relate training practices to injury occurrence. Data was gathered from the responses of 95 competitors (75 men, 20 women) in the 1986 Hawaii Ironman Triathlon who completed a training and medical history questionnaire. In this sample, virtually all (91%) sustained at least one soft tissue, overuse injury during the previous year's training. The area of the body most frequently involved was the back, but the most common pattern was to have multiple areas involved. Because of the consistent combinations of injuries, mechanical abnormalities, such as diminished shock absorption, may have contributed to injury. Training habits were extremely variable and not directly related to either the incidence or type of injury.

Adult↗