The effect of endurance swimming on the cardiorespiratory fitness levels of sedentary, middle aged men and women

Twelve middle aged men and women (23-59 years) participated in twelve weeks (36 sessions) of endurance swim training at an approximate intensity of 75% maximum heart rate (Karvonen Method) (14). This training resulted in improved cardiorespiratory fitness as evidenced by a significant (9.4%) increase in mean maximal oxygen uptake (liters/ min.) and a significant bradycardial response during submaximal walking. Subjects lost significant amounts of subcutaneous body fat, as measured by skinfold calipers, but experienced very little change in absolute body weight (.1 kg.) suggesting an increase in muscle weight. Data from the submaximal walking test, administered after each 12 session period of training, showed a nonlinear decline in heart rate throughout training. This, possibly, was in response to an accumulating fatigue factor brought on by a rapid increase in the amount of total work that the subjects were doing during the middle stage of training.Thesis (M.A.

Long-Term Impact of Living and Learning at High Altitude: An Altitude Physiology Class for Undergraduate Students

Alma College initiated an Altitude Physiology class in 1997 devoted to living and learning at high altitude (3440 m). The class incorporated several key elements of High-Impact Educational Practice including a strong student-research component and collaborative groups assignments. A retrospective survey was administered to alumni of the class to determine its long-term impact. Student responses ranged from “agree” to “strongly agree” with statements regarding the class’s impact on positive learning outcomes such as critical thinking, knowledge acquisition, synthesis of knowledge, and understanding of research. Students generally favored non-traditional formats such as living at altitude for gaining understanding of environmental physiology

Long-Term Impact of Living and Learning at High Altitude: An Altitude Physiology Class for Undergraduate Students

Alma College initiated an Altitude Physiology class in 1997 devoted to living and learning at high altitude (3440 m). The class incorporated several key elements of High-Impact Educational Practice including a strong student-research component and collaborative groups assignments. A retrospective survey was administered to alumni of the class to determine its long-term impact. Student responses ranged from “agree” to “strongly agree” with statements regarding the class’s impact on positive learning outcomes such as critical thinking, knowledge acquisition, synthesis of knowledge, and understanding of research. Students generally favored non-traditional formats such as living at altitude for gaining understanding of environmental physiology

Renal responsiveness to aldosterone during exposure to simulated microgravity

We measured renal functions and hormones associated with fluid regulation after a bolus injection of aldosterone (Ald) during head-down tilt (HDT) bed rest to test the hypothesis that exposure to simulated microgravity altered renal responsiveness to Ald. Six male rhesus monkeys underwent two experimental conditions (HDT and control, 72 h each) with each condition separated by 9 days of ambulatory activities to produce a crossover counterbalance design. One test condition was continuous exposure to 10° HDT; the second was a control, defined as 16 h per day of 80° head-up tilt and 8 h prone. After 72 h of exposure to either test condition, monkeys were moved to the prone position, and we measured the following parameters for 4 h after injection of 1-mg dose of Ald: urine volume rate (UVR); renal Na+/K+ excretion ratio; renal clearances of creatinine, Na+, osmolality, and free water; and circulating hormones [Ald, renin activity (PRA), vasopressin (AVP), and atrial natriuretic peptide (ANP)]. HDT increased Na+ clearance, total renal Na+ excretion, urine Na+ concentration, and fractional Na+excretion, compared with the control condition, but did not alter plasma concentrations of Ald, PRA, and AVP. Administration of Ald did not alter UVR, creatinine clearance, Ald, PRA, AVP, or ANP but reduced Na+ clearance, total renal Na+ excretion, urinary Na+/K+ ratio, and osmotic clearance. Although reductions in Na+ clearance and excretion due to Ald were greater during HDT than during control, the differential (i.e., interaction) effect was minimal between experimental conditions. Our data suggest that exposure to microgravity increases renal excretion of Na+ by a natriuretic mechanism other than a change in renal responsiveness to Ald