Charles M Tipton

• Ph.D in Physiology
• University of Arizona

Despite the availability and utilization of the physiology textbooks authored by Albrecht von Haller during the 18(th) century that heralded the modern age of physiology, not all physicians were satisfied with its presentation, contents, or application to medicine. Initial reasons were fundamental disagreements between the " mechanists" represented...

This invited autobiographical article pertains to 52 years as an exercise physiologist of which 16 years were devoted to being an active emeriti. Although the career pathway was circuitous in nature, once resolved, it included preparation of future exercise physiologists; reducing the health hazards associated with the "making of weight" by scholas...

Carl Vincent Gisolfi (1942-2008) was a Distinguished Professor of Exercise Science at the University of Iowa whose contributions included mentoring future investigators and seminal studies in the areas of thermoregulation during exercise, responses of the diencephalon to elevated temperatures, fluid absorption during heat stress, and the role of he...

In 2007, the American College of Sports Medicine, with endorsement from the American Medical Association and the Office of the Surgeon General, launched a global initiative to mobilize physicians, healthcare professionals and providers, and educators to promote exercise in their practice or activities to prevent, reduce, manage, or treat diseases t...

Society members whose research publication during the past 125 yr had an important impact on the discipline of physiology were featured at the American Physiological Society (APS)'s 125th Anniversary symposium. The daunting and challenging task of identifying and selecting significant publications was assumed by the Steering Committee of the Histor...

Within the archives of Springfield College are the unofficial minutes of the Gulick Academy of Physical Education from 1906–1909. Surprisingly, the attendance, participation, and presentations of Clark W. Hetherington were not very impressive, which raised the question, what had he accomplished to warrant the Academy designating him as its first me...

In 2005, the American Physiological Society (APS) initiated the Living History of Physiology Archival Program to recognize senior members who have made significant contributions during their career to the advancement of the discipline and the profession of physiology. Subsequently, the leadership of the APS Section of Environmental and Exercise Phy...

In 2005, the American Physiological Society (APS) initiated the Living History Project to recognize senior members who have made significant contributions during their career to the advancement of the discipline and profession of physiology. During 2007, the APS Section of Environmental and Exercise Physiology selected Prof. G. Edgar Folk, Jr., of...

When considering the history of exercise physiology, authors begin with Hippocrates and the "Golden Age" of Greece before mentioning Galen and the contributions from Rome. However, this approach has omitted the information from the ancient civilizations of India which flourished before and during the emergence of Mycenaen cultures. Specifically ign...

Tryptophan and quinolinic acid, inhibitors of gluconeogenesis, were used to block the removal of lactate by the liver in order to investigate the involvement of the Cori cycle in oxygen debt. Five male, mongrel dogs were run on a treadmill at 4 mph with a 20 percent grade for 19 min. The mean exercise [(V)\dot]O2 \dot V_{O_2 } was 80.673.11 ml/kg/m...

At the first International Congress of Physiologists in Basel, Switzerland, the Italian physiologist Angelo Mosso (1846-1910) discussed his findings on muscular fatigue while demonstrating the functioning of an ergograph (work recorder). One hundred sixteen years later, Mosso's career, scientific accomplishments, and legacy in the study of muscular...

To determine the contributions made by Academy Fellows during the past 75 years to concepts within the body of knowledge associated with exercise physiology, a literature search was undertaken. Of the charter Fellows, Hetherington and eight others (34%) were identifi ed. Schneider in 1933 was the fi rst of 18 Fellows who became authors, co-authors,...

It is a daunting task to present in a cohesive chapter a historical perspective on the functions of the autonomic nervous system during exercise by normal and physically trained subjects. The multiplicity of systems regulated by the autonomic nervous system is summarized as follows by Hamill (76, p. 12): The autonomic nervous system (ANS) is struct...

This is the first history of exercise physiology written from a systems perspective. The significance of human exercise experiments is emphasized, and the range of coverage is very wide. Among the figures whose thinking or work are discussed are Galen, Avicenna, Descartes, Edward Smith, Seguin, Krogh, A.V. Hill, Henry Taylor, Zuntz, Ingle, Palladin...

Although humans have experienced microgravity since 1961, it is unknown whether PaO2 or PaCO2 will change in humans or in animals exposed to similar conditions. Reports from subjects participating in long-term head down tilt studies indicate that PAO2 will decrease and PaCO2 will increase, presumably because of impairments in oxygen delivery and ca...

The relationships between the discipline of exercise physiology and the activities of the Harvard Fatigue Laboratory were examined. Even though 5 decades have elapsed since the Laboratory's closure, its existence, leaders, and accomplishments continue to be revered by exercise physiologists. The Laboratory was unique because it was the first resear...

1. Since ancient times, athletes have consumed proteins because of the belief they were the necessary substrate for optimal performance. Even though this concept was proven to be incorrect before the beginning of the 19th century, the practice continued until several decades ago. 2. By 1939, careful metabolic investigations on the changes in the re...

We examined skeletal and cardiac muscle responses of mature (8 mo) and old (23 mo) male Fischer 344 rats to 14 days of hindlimb suspension. Hexokinase (HK) and citrate synthase (CS) activities and GLUT-4 glucose transporter protein level, which are coregulated in many instances of altered neuromuscular activity, were analyzed in soleus (Sol), plant...

According to the international Olympic Committee, it is the responsibility of the sports medicine profession to care for the health and welfare of Olympic athletes, treat and prevent injuries, conduct medical examinations, evaluate performance capacity, provide nutritional advice, prescribe and supervise training programs, and to monitor substance...

Post-spaceflight results and findings from humans and rodents after conditions of bed rest or simulated microgravity indicate maximum exercise performance is significantly compromised. However, the chronic administration of dobutamine (a synthetic adrenomimetic) to humans in relevant experiments improves exercise performance by mechanisms that prev...

Rats exposed to simulated conditions of microgravity exhibit reductions in aerobic exercise capacity that may be due to an impaired ability of the sympathetic nervous system (SNS) to mediate an increase in cardiac output and to redistribute blood flow. The purpose of this study was to quantify the sympathetic response to exercise in rats after expo...

Although Kroll's textbooks for physical educators have acknowledged the achievements of Fitz, McArdle, Hatch and Katch appear to be the only authors of textbooks for undergraduate or graduate students in exercise physiology to mention his name or contributions. Fitz received an H.D. from Harvard in 1891 and subsequently became an instructor in the...

Two prominent theories to explain the physiological effects of microgravity relate to the cascade of changes associated with the cephalic shifts of fluids and the absence of tissue deformation forces. One-g experiments for humans used bed rest and the head-down tilt (HDT) method, while animal experiments have been conducted using the tail-suspended...

The Centennial of the modern Olympic movement was celebrated summer, 1996, in Atlanta, Georgia. As part of the Olympic centennial year, the American Institute of Nutrition, History of Nutrition Committee, sponsored a symposium in Washington DC to examine nutrition and physical performance, and to review historical and contemporary data on athletic...

Since 1961, there have been more than 165 flights involving several hundred individuals who have remained in a space environment from 15 min to more than a year. In addition, plans exist for humans to explore, colonize, and remain in microgravity for 1000 d or more. This symposium will address the current state of knowledge in select aspects associ...

Despite the fact that the first human was in space during 1961 and individuals have existed in a microgravity environment for more than a year, there are limited spaceflight data available on the responses of the neuroendocrine and immune systems. Because of mutual interactions between these respective integrative systems, it is inappropriate to as...

Studies by others have shown that chronic dobutamine injections will minimize the loss in aerobic capacity of humans assigned to bed rest conditions or of rats in a head-down, tail suspended position (HOT). To determine whether this bcta-1 sympathetic agonist (D) would modify metabolic responses as evaluated by blood measures of lactic acid (LA), p...

Rats exposed to simulated conditions of microgravity by head-down suspension (HDS) exhibit reductions in aerobic capacity. This may be due to an impaired ability to augment cardiac output and to redistribute blood flow during exercise. The purpose of this investigation was to measure cardiac output and blood flow distribution in rats that were expo...

Measurements from mission specialists after space flights or from subjects subjected to head down tilt experiments have demonstrated a decrease in exercise performance. Similar decreases have been reported for rats that have participated in simulated microgravity studies using the head down-tail suspended method of Morey-Holton (HDS). Because it is...

The primary purpose of this investigation was to secure select anatomical and physiological measurements from hypophysectomized rats and their sham-operated control to determine how various endocrine influences could be modified by conditions of simulated microgravity. The focal point of the study was the exercise responses after head-down suspensi...

On earth, the presence of gravity imposes weight-bearing gradients on tissues which influence the functions of multiple integrative systems. On the other hand, conditions of actual or simulated microgravity can modify and/or nullify these gradients and subsequently alter structure and function. The purpose of this symposium is to discuss the result...

Rats exposed to head-down suspension (HDS) exhibit reductions in maximal O2 consumption (VO2max) and atrophy of select hindlimb muscles. This study tested the hypothesis that an endocrine-deficient rat exposed to HDS would not exhibit reductions in VO2max or hindlimb muscle mass. Hypophysectomized (HYPX) and sham-operated (SHAM) rats were tested fo...

We investigated the effects of purified histone H4 on glucose transport activity in rat soleus and flexor digitorum brevis muscles. Histone H4, at concentrations up to 11.8 microM, increased 2-deoxyglucose (2-DG) uptake in a dose-dependent fashion. However, at concentrations higher than 11.8 microM, H4 caused a decrease in 2-DG uptake from the maxi...

Head-down suspension (HDS) of rats has evolved as a useful model for the simulation of a microgravity environment. Previous HDS experiments with rats have shown an impaired capacity to perform aerobic exercise as demonstrated by reductions in maximum oxygen consumption (VO2 max), treadmill run time (RT), and mechanical efficiency (ME) of treadmill...

This study was designed to examine the effect of non-weight-bearing conditions and the systemic influences of simulated microgravity on rat hindlimb muscles. For this purpose, rats were suspended (SUS) in a head-down position (45 degrees) with the left hindlimb non-weight bearing (NWB) and the right hindlimb bearing 20% of presuspension body mass (...

The effects of microgravity and endurance training (TR) on maximal O2 consumption was investigated in trained and nontrained (NT) rats subjected to head-down suspension (HDS) by comparing maximal O2 consumption, treadmill run time (RT), and mechanical efficiency (ME) of treadmill running in HDS rats, both NT and TR, and in respective cage controls....

This study was designed to examine insulin- and exercise-stimulated glucose uptake and metabolism in the hindlimb muscles of rats after conditions of simulated microgravity. To simulate microgravity, male Sprague-Dawley rats were suspended in a head-down (45 degrees) position with their hindlimbs non-weight bearing (SUS) for 14 days. In addition, r...

To study the influences of 16 wk of endurance training on the reflex regulation of resting blood pressure, nontrained (NT) and trained (T) female hypertensive rats (SHR) were subjected to conditions of lower body negative pressure (LBNP). Measurements of muscle cytochrome oxidase activity and run time to exhaustion indicated that the animals were e...

Prior exercise increases insulin sensitivity for glucose and system A neutral amino acid transport activities in skeletal muscle. Insulin-like growth factor I (IGF-I) also activates these transport processes in resting muscle. It is not known, however, whether prior exercise increases IGF-I action in muscle. Therefore we determined the effect of a...

Our purpose was to determine if endurance exercise training would increase the oxidative capacity of the abdominal expiratory muscles of the rat. Accordingly, 9 male rats were subjected to an endurance training protocol (1 h/day, 6 days/week, 9 weeks) and 9 litter-mates served as controls. Citrate synthase (CS) activity was used as an index of oxid...

Results from previous studies have shown that the reduction in maximal oxygen consumption (VO2max) with simulated microgravity is attenuated in chemically sympathectomized rats. To determine the contributions of the catecholamines from the adrenal medulla in this process, investigations were conducted with 65 saline injected (SAL) and chemically sy...

Studies with male spontaneously hypertensive rats (SHR) were initiated to determine the hemodynamic relationships associated with the lower resting caudal artery systolic blood pressure (SBP) of endurance-trained SHR populations. After assignment into nontrained (NT, n = 38) and trained (T, n = 38) groups, the T animals were exercised 5 times/wk on...

To determine the time course of changes in maximal oxygen consumption (VO2max) and its relationships with body composition, a 29-d simulated microgravity study was initiated with 30 adult female rats (230-280 g) randomly assigned to one of three experimental groups; namely, head-down suspension (HDS) at 45 degrees, horizontal suspension (HS) at 0 d...

This study determined the validity of previously published or newly derived equations to predict fat-free body mass (FFB) in high school wrestlers from the midwestern United States. Five laboratories participated in the data-pooling study (total sample of 860 subjects). Measures included body composition by underwater weighing and anthropometric me...

Maximum oxygen consumption (VO2max) has been shown to be reduced after periods of simulated weightlessness. To assess the role of the sympathetic nervous system in these reductions, Sprague-Dawley rats were either chemically sympathectomized (SYMX) or injected with saline (SHAM) and assigned to head-down suspension (HDS), horizontal restraint with...

The purpose of this study was to determine the systemic hemodynamic mechanism(s) underlying the pressor response to nonexertional heat stress in the unrestrained conscious rat. After a 60-min control period [ambient temperature (Ta) 24 degrees C], male Sprague-Dawley rats (260-340 g) were exposed to a Ta of 42 degrees C until a colonic temperature...

The purpose of this study was to test the hypothesis that the cardiovascular and sympathoadrenal responses to acute environmental stress are attenuated by exercise training. Furthermore, we tested the hypothesis that the cardiovascular and sympathoadrenal responses to intracerebroventricular (ICV) administration of corticotropin-releasing factor (C...

The purpose of this study was to test the hypothesis that the cardiovascular-sympathetic nervous system adjustments during nonexertional heat stress are exaggerated in senescent (S, 24 mo) vs. mature (M, 12 mo) conscious unrestrained Fischer 344 rats. During two separate trials (48 h apart), each animal was exposed to an ambient temperature (Ta) of...

The purpose of this study was to determine if the arterial baroreceptor reflexes modulate the sympathocirculatory responses to acute heat stress. To address this, arterial pressure, heart rate, mesenteric and renal blood flow velocity (Doppler flow probes), arterial plasma norepinephrine, and colonic temperature were measured before and during whol...

The purpose of this study was to test the hypothesis that the rise in colonic temperature (Tc) during nonexertional heat stress is exaggerated in senescent (SEN, 24 mo, n = 12) vs. mature (MAT, 12 mo, n = 15) conscious unrestrained Fischer 344 rats. On 2 separate days (48 h apart) each SEN and MAT animal was exposed to an ambient temperature (Ta) o...

To assess the effects of moderate exercise [40-70% maximal oxygen uptake (VO2max)] on resting blood pressures, the presence of cerebrovascular lesions, and the life spans of stroke-prone hypertensive rats, nontrained and trained male and female rats were assigned to two experimental groups. The first (n = 48) were exercise trained after 38 days of...

The effects of intracerebroventricular (icv) administration of a corticotropin-releasing factor (CRF) receptor antagonist, alpha-helical CRF, on systemic and regional hemodynamic adjustments to exercise were studied in conscious rats. On consecutive days, rats received saline icv, alpha-helical CRF icv, and no treatment 30 min before treadmill exer...

Mature male rats (n = 16) were assigned to either 14 days of head-down suspension with one hindlimb supported (HDS) or to control cages (C) of similar dimensions. Hindlimb support during HDS preserved the muscle mass-to-body mass ratio (mg/100g) compared with C conditions for the soleus (48.3 +/- 1.0 to 41.7 +/- 1.0), plantaris (98.4 +/- 3.4 to 103...

To determine whether hindlimb suspension is associated with the development of cardiovascular deconditioning, male rats were studied before and after undergoing one of three treatment conditions for 9 days: 1) cage control (n = 15, CON), 2) horizontal suspension (n = 15, HOZ), and 3) head-down suspension (n = 18, HDS). Testing included lower body n...

Studies were undertaken with adult male rats to test the hypothesis that euglycemic hyperinsulinemia would alter mean arterial blood pressure (MAP) and heart rate (HR) relationships by activation of the sympathetic nervous system. Conscious rats were infused either with insulin or control vehicle (0, 0.47, 1.5, 4.7, 15.0 mU.kg-1.min-1) for 75 min b...

Male rodents were studied before and after undergoing one of three treatment conditions for 9 days: 1) cage control (n = 15, CON), 2) horizontal suspension (n = 15, HOZ), and 3) head-down suspension (n = 18, HDT). Testing included measurements of maximal O2 uptake (VO2 max) and select cardiovascular responses to graded treadmill exercise. VO2 max e...

Previous research by Tcheng and Tipton developed two prediction equations appropriate for the estimation of minimal weight for high school wrestlers. The purpose of this investigation was to cross-validate these equations using densitometric estimates of minimal weight. Skeletal dimension measurements and hydrostatic weighing were completed on 220...

To determine whether chronic static exercise would alter resting caudal artery systolic blood pressure (RSBP) in stroke-prone hypertensive rats (SP-SHR), a 20- to 21-wk experimental study was initiated with 24 male and 16 female rats. In addition, eight rats were cannulated for heart rate and blood pressure measurements and implemented with Doppler...

Postexercise reductions in blood pressure at rest have been reported for hypertensive subjects. To determine whether post-exercise hypotension would occur in spontaneously hypertensive rats and to test the hypothesis that any reductions would result because of decreases in regional vascular resistances, hypertensive rats (n = 19) were instrumented...

To test the hypothesis that endurance training would attenuate the carotid sinus baroreflex in rats, studies were undertaken with 25 nontrained (NT) and 22 trained (T) male Sprague-Dawley rats that were exercised for 11-14 wk. Maximal O2 consumption was significantly increased 10% after training. The left carotid sinus region was functionally isola...