Advantages of smaller body mass during distance running in warm, humid environments

The purpose of this study was to examine the extent to which lighter runners might be more advantaged than larger, heavier runners during prolonged running in warm humid conditions. Sixteen highly trained runners with a range of body masses (55-90 kg) ran on a motorised treadmill on three separate occasions at 15, 25 or 35 degrees C, 60% relative humidity and 15 km x h(-1) wind speed. The protocol consisted of a 30-min run at 70% peak treadmill running speed (sub-max) followed by a self-paced 8-km performance run. At the end of the submax and 8-km run, rectal temperature was higher at 35 degrees C (39.5+/-0.4 degrees C, P<0.05) compared with 15 degrees C (38.6+/-0.4 degrees C) and 25 degrees C (39.1+/-0.4 degrees C) conditions. Time to complete the 8-km run at 35 degrees C was 30.4+/-2.9 min (P<0.05) compared with 27.0+/-1.5 min at 15 degrees C and 27.4+/-1.5 min at 25 degrees C. Heat storage determined from rectal and mean skin temperatures was positively correlated with body mass (r=0.74, P<0.0008) at 35 degrees C but only moderately correlated at 25 degrees C (r=0.50, P<0.04), whereas no correlation was evident at 15 degrees C. Potential evaporation estimated from sweat rates was positively associated with body mass (r=0.71, P<0.002) at 35 degrees C. In addition, the decreased rate of heat production and mean running speed during the 8-km performance run were significantly correlated with body mass (r=-0.61, P<0.02 and r=-0.77, P<0.0004, respectively). It is concluded that, compared to heavier runners, those with a lower body mass have a distinct thermal advantage when running in conditions in which heat-dissipation mechanisms are at their limit. Lighter runners produce and store less heat at the same running speed; hence they can run faster or further before reaching a limiting rectal temperature.     

Relationships of depression and anxiety to readmission rates among patients with diabetes from Harare and Parirenyatwa referral hospitals in Zimbabwe

BackgroundThe knowledge of determinants of readmission among individuals with diabetes minimises relapse and decreases diabetes associated morbidity and mortality.ObjectivesTo explore the prevalence of depression and anxiety as well as determinants of readmission in individuals with diabetes from Harare, Zimbabwe.MethodsA cross sectional study was carried out at Parirenyatwa and Harare group of hospitals. Participants were recruited through purposive sampling and interviewed at the diabetic clinics. Depression and anxiety were measured using the Hospital Anxiety and Depression Scale. Binary logistic regression was used to determine predictors of readmission.ResultsIn total 65 participants took part, 36.9% were males. The mean age ±SD was 44.89±14.2 years. Anxiety affected 40% and 20% were at risk of anxiety, while depression was reported in 27.7% and 30.8% were at risk of depression. Depression [OR=0.64, 95%CI: 0.42–0.97 (p=0.037)] and checking of blood glucose [OR=0.06, 95%CI: 0.01–0.71 (p=0.025)] were significant negative predictors of readmission among diabetic patients while anxiety was a significant positive predictor OR=1.55, 95%CI: 1.09–2.21 (p=0.015).ConclusionsMental health conditions in people living with diabetes are factors contributing to increased re admissions and are more prevalent with aging. Psychotherapy and education interventions are recommended for the elderly diabetic population.     

Running economy of African and Caucasian distance runners

PURPOSE: Anecdotal evidence suggests an advantageous physiological endowment of the African endurance athlete. Higher fractional utilization of VO2max has been suggested but not measured directly, and investigations of running economy have been inconclusive. The aim of the current study was to measure a) running economy and b) fractional utilization of VO2max, in African and Caucasian 10-km runners of similar body mass. METHODS: Eight African and eight Caucasian runners had no significant difference in mean race time (32.8 +/- 2.8, 32.0 +/- 2.5 min, respectively), body mass (61.4 +/- 7.0, 64.9 +/- 3.0 kg), age, body fat, or lean thigh volume. Caucasian runners were 6 cm taller (P < 0.05). Subjects completed a progressive treadmill VO2peak test. On a separate day, subjects completed two 6-min workloads (16.1 km x h(-1) and 10-km race pace) separated by 5 min. RESULTS: Mean VO2peak was 13% lower in the Africans (61.9 +/- 6.9, 69.9 +/- 5.4 mL x kg(-1) x min(-1), P = 0.01). At 16.1 km x h(-1), the Africans were 5% more economical (47.3 +/- 3.2, 49.9 +/- 2.4 mL x kg(-1) x min(-1), P < 0.05). This difference increased to 8% (P < 0.01) when standardized per kg(0.66). At race pace, the Africans utilized a higher %VO2peak (92.2 +/- 3.7, 86.0 +/- 4.8%, P < 0.01) and had higher HR (185 +/- 9, 174 +/- 11 b x min(-1), P < 0.05) and plasma [ammonia] (113.2 +/- 51, 60.3 +/- 16.9 micromol x L(-1), P < 0.05). Despite the higher relative workload, the plasma [lactate] was not different (5.2 +/- 2.0, 4.2 +/- 1.7 mmol x L(-1), NS). CONCLUSIONS: This study indicates greater running economy and higher fractional utilization of VO2peak in African distance runners. Although not elucidating the origin of these differences, the findings may partially explain the success of African runners at the elite level.     

Understanding the Reasons for Deferring ART Among Patients Diagnosed Under the Same-Day-ART Policy in Johannesburg,South Africa

We aimed to examine the correlates of antiretroviral therapy (ART) deferral to inform ART demand creation and retention interventions for patients diagnosed with HIV during the Universal Test and Treat (UTT) policy in South Africa. We conducted a cohort study enrolling newly diagnosed HIV-positive adults (≥?18 years), at four primary healthcare clinics in Johannesburg between October 2017 and August 2018. Patients were interviewed immediately after HIV diagnosis, and ART initiation was determined through medical record review up to six-months post-test. ART deferral was defined as not starting ART six months after HIV diagnosis. Participants who were not on ART six-months post-test were traced and interviewed telephonically to determine reasons for ART deferral. Modified Poisson regression was used to evaluate correlates of six-months ART deferral. We adjusted for baseline demographic and clinical factors. We present crude and adjusted risk ratios (aRR) associated with ART deferral. Overall, 99/652 (15.2%) had deferred ART by six months, 20.5% men and 12.2% women. Baseline predictors of ART deferral were older age at diagnosis (adjusted risk ratio (aRR) 1.5 for 30–39.9 vs 18–29.9 years, 95% confidence intervals (CI): 1.0–2.2), disclosure of intentions to test for HIV (aRR 2.2 non-disclosure vs disclosure to a partner/spouse, 95% CI: 1.4–3.6) and HIV testing history (aRR 1.7 for? >?12 months vs?<?12 months/no prior test, 95% CI: 1.0–2.8). Additionally, having a primary house in another country (aRR 2.1 vs current house, 95% CI: 1.4–3.1) and testing alone (RR 4.6 vs partner/spouse support, 95% CI: 1.2–18.3) predicted ART deferral among men. Among the 43/99 six-months interviews, women (71.4%) were more likely to self-report ART initiation than men (RR 0.4, 95% CI: 0.2–0.8) and participants who relocated within SA (RR 2.1 vs not relocated, 95% CI: 1.2–3.5) were more likely to still not be on ART. Under the treat-all ART policy, nearly 15.2% of study participants deferred ART initiation up to six months after the HIV diagnosis. Our analysis highlighted the need to pay particular attention to patients who show little social preparation for HIV testing and mobile populations.

     

Self-reported motivators for HIV testing in the treat-all era among HIV positive patients in Johannesburg,South Africa

To explore associations between self-reported ill-health as a primary motivator for HIV-testing and socio-demographic factors.Four local primary healthcare clinics in Johannesburg, South Africa.A total of 529 newly HIV diagnosed adults (≥18 years) enrolled from October 2017 to August 2018, participated in the survey on the same day of diagnosis.Testing out of own initiative or perceived HIV exposure was categorized as asymptomatic. Reporting ill-health as the main reason for testing was categorized as symptomatic. Modified Poisson regression was used to evaluate predictors of motivators for HIV testing.Overall, 327/520 (62.9%) participants reported symptoms as the main motivator for testing. Among the asymptomatic, 17.1% reported potential HIV exposure as a reason for testing, while 20.0% just wanted to know their HIV status. Baseline predictors of symptom-related motivators for HIV testing include disclosing intention to test (aPR 1.4 for family/friend/others vs partners/spouse, 95% CI: 1.1–1.8; aPR 1.4 for not disclosing vs partners/spouse, 95% CI: 1.1–1.7), and HIV testing history (aPR 1.2 for last HIV test >12-months ago vs last test 12-months prior, 95% CI: 1.0–1.5; aPR 1.3 for never tested for HIV before vs last test 12-months prior, 95%CI:1.0–1.6).Findings indicate that newly diagnosed HIV positive patients still enter care because of ill-health, not prevention purposes. Increasing early HIV testing remains essential to maximize the benefits of expanded ART access.     

The effects of heat stress on neuromuscular activity during endurance exercise

This study analysed the effect of hot (35 degrees C) and cold (15 degrees C) environments on electromyographic (EMG) signal characteristics, skin and rectal temperatures and heart rate during progressive endurance exercise. Eight healthy subjects performed three successive 15-min rides at 30%, 50% and 70% of their peak sustained power output and then cycled at increasing (15 W/min) work rates to exhaustion in both 35 degrees C and 15 degrees C environments. Skin and rectal temperatures, heart rate and EMG data were measured during the trials. The skin temperatures were higher and the subjects felt more uncomfortable in the hot conditions (Bedford scale) ( P<0.01). Rectal temperature was slightly, but not significantly, higher under hot conditions. Heart rate was significantly higher in the hot group (between condition P<0.05). Peak power output (267.4+/-67.7 W vs. 250.1+/-61.5 W) and time-to-exhaustion (55.7+/-16.7 min vs. 54.5+/-17.1 min) (COLD vs. HOT) were not different between conditions. There were no differences in integrated EMG (IEMG) or mean power frequency spectrum between conditions. Rating of perceived exertion increased similarly in both conditions over time. Although the hot conditions increased heart rate and skin temperature, there were no differences in muscle recruitment or maximal performance, which suggests that the thermal stress of 35 degrees C, in combination with exercise, did not impair maximal performance in this study.     

A job analysis of selected health workers in a district health system in KwaZulu-Natal. Part three: Other categories of health workers

This article described the third part of a study aimed at doing a job analysis of nurses and non-professional health workers in a district health system. This article describes the tasks of five categories of workers, their training and their work-load over an ordinary week. Interviews were done with 52 workers from three hospitals and five clinics, of whom 14 were men and 38 women. The three PHC guards had a much more varied job than the hospital security staff (also three). All of them have had specific task related training. The six General Assistants in Primary Health Care settings were almost exclusively involved in cleaning, while the 23 in hospitals added food and drink management and running errands to their work. Only one had training pertaining to the specific tasks. All three clerks were found in the PHC setting, and their tasks were mainly that of receptionist. None had specific task related training. The three Ground's Men worked at gardening and cleaning at PHC clinics, but a range of other tasks were added from time to time. Porters, of whom ten were interviewed, did mainly transporting of patients and running errands. GA's and security staff were also used to control violent patients and visitors, something for which none of them have had training. Recommendations were made about training and work redesign in the district.