EFFECT OF TEMPERATURE AND EXERCISE ON LIMB BLOOD FLOW

EFFECT OF TEMPERATURE AND EXERCISE ON LIMB BLOOD FLOW

ABSTRACT

This study explores the impact of temperature and exercise on limb blood flow in humans, focusing on awareness, perceptions, and their practical implications. The research was conducted with a sample size of athletes in Enugu Metropolis, Nigeria using closed-ended questionnaires. The chapter aimed to investigate the impact of temperature and exercise on limb blood flow in humans, as well as the relationship between exercise activities, temperature, and limb blood flow. The research questions focused on understanding the athletes’ knowledge and awareness regarding these aspects of limb blood flow regulation. Data was collected through closed-ended questionnaires distributed to the athletes. The questionnaires utilized a 4-point rating scale ranging from Strongly Agree (SA) to Strongly Disagree (SD). The participants provided their responses, indicating their level of agreement with each statement. Respondents demonstrated a commendable level of awareness and understanding regarding temperature, exercise, and limb blood flow. Participants believed in the importance of maintaining appropriate limb blood flow during exercise and acknowledged the significance of these factors for athletic performance. The hypothesis that posited a relationship between exercise activities, temperature, and limb blood flow (ρ > 0) was supported by statistically significant positive correlations between all variables. Based on the study’s findings, we recommend the implementation of comprehensive educational programs for athletes to enhance their knowledge of how temperature and exercise affect limb blood flow. These programs should empower athletes to actively monitor and manage these factors to optimize their health and performance.

 

 

 

CHAPTER ONE

INTRODUCTION

1.1      Background of the Study

The human body maintains a delicate balance between heat production and heat dissipation to ensure optimal physiological functioning. Exercise and environmental temperature are two key factors that can significantly influence this balance. During exercise, the body activates various mechanisms to increase heat production, such as increased metabolic rate and muscle contractions. Additionally, environmental temperature can either enhance or impede the body’s ability to dissipate heat effectively. One crucial aspect affected by the interplay between temperature and exercise is limb blood flow. Blood flow to the limbs plays a vital role in supplying oxygen and nutrients to the working muscles, removing metabolic waste products, and regulating body temperature. Understanding the effects of temperature and exercise on limb blood flow is crucial for optimizing performance, preventing injuries, and improving overall human health.

Local tissue and blood temperature (TB) increase with elevations in skeletal muscle metabolism and heat production during dynamic exercise (Sproule & Archer, 1959; Saltin & Hermansen, 1966; Gonzalez-Alonso et al. 1999, 2000). However, the influence of temperature on perfusion in exercising and non-exercising human limbs is not established. In humans, the increases in local perfusion and oxygen uptake (V˙ O2 ) during leg exercise are much greater than during arm exercise, reflecting differences in muscle mass and work capacity (Secher et al. 1977; Knight et al. 1992; Volianitis & Secher, 2002; Calbet et al. 2004; Mortensen et al. 2005). Limb tissue and blood temperatures depend upon the balance between heat production and endogenous heat transfer. In exercising limbs, heat is transferred from the working muscles to the neighboring tissues and the overlying skin as well as to the body core. This is made possible via the flowing blood (convective heat transfer) and direct intercellular heat conduction (conductive heat transfer; Barcroft & Edholm, 1943; Pennes et al. 1948; Gonzalez-Alonso ´ et al. 2000). Differences in V˙ O2 and thus metabolic heat production between the exercising lower and upper limbs could affect the increase in TB and the relationship between TB and perfusion in exercising and non-exercising limbs if the differences in heat production are not matched by proportional changes in endogenous heat transfer. To date, no study has examined the relationships amongst limb TB, perfusion, and aerobic metabolism during separate and combined lower and upper limb exercise to determine whether a coupling between TB and limb perfusion is still apparent when accounting for differences in metabolism and heat production. Understanding of thermoregulation during exercise is largely based on the regulation of skin blood flow and sweating in resting limbs (Johnson et al. 2014). Yet the local thermal stimuli modulating these key thermoregulatory responses during exercise are likely to be different in the exercising and non-exercising limbs unless increases in temperature in the exercising limbs lead to similar elevations in blood and tissue temperature in the non-exercising limbs. The net heat transfer from the exercising limbs to the trunk and head results in increased core and brain temperatures (Saltin et al. 1966; Nybo et al. 2002; Kenny et al. 2003; Trangmar et al. 2014). In non-exercising limbs during prolonged leg exercise, however, forearm venous TB and muscle temperature are lower and do not increase to the same extent as core and active leg muscle and blood temperatures (Gonzalez-Alonso ´ et al. 1999; Jay et al. 2007). To shed light on the mechanisms of temperature and limb blood-flow regulation, it is timely to investigate the impact of hemodynamic and thermodynamic events in exercising limbs on central and non-exercising limb perfusion and TB. Temperature is one of a congregate of metabolic byproducts proposed to contribute to the regulation of limb tissue perfusion (Barcroft & Edholm, 1943). In support of a role for hyperthermia, increases in local blood and muscle temperatures are associated with similar elevations in limb perfusion during both isolated leg and whole-body heat stress (Pearson et al. 2011; Heinonen et al. 2011; Chiesa et al. 2015), irrespective of differences in systemic temperature and hemodynamic responses between conditions (Chiesa et al. 2015).

1.2 Statement of the Problem

Although small compared with exercise hyperemia, this hyperthermia-mediated limb hyperemia is maintained during combined heat stress and one-legged knee-extensor exercise (Pearson et al. 2011; Chiesa et al. 2015). The thermal hyperemia in resting limbs is associated only in part with metabolic vasodilatation because the concomitant elevation in limb V˙ O2 is too small to account for the increase in perfusion (Pearson et al. 2011; Chiesa et al. 2015). Thus, hyperthermia induces vasodilatation of the limb tissue vascular beds through other mechanisms, which may be temperature sensitive. Along these lines, hyperthermia is associated with elevations in the intravascular concentration of the potent vasoactive substance ATP (Pearson et al. 2011), accompanying skeletal muscle, skin, and bone vasodilatation (Heinonen et al. 2011; Pearson et al. 2011). During exercise in normal environmental conditions, plasma ATP also increases in the forearm and leg circulations (Forrester & Lind, 1969; Forrester, 1972; Gonzalez-Alonso et al. 2002; Mortensen et al. 2011), possibly in response to alterations in erythrocyte oxygen binding and other adjuvant metabolic, thermal and mechanical stimuli (Bergfeld & Forrester, 1992; Ellsworth et al. 1995; Sprague et al. 1998; Wan et al. 2008; Kalsi & Gonzalez-Alonso, 2012).

 

1.3 Objectives of the Study

The primary objective of this study is to investigate the impact of motivation on oral health delivery among dental therapists in Enugu Metropolis, Nigeria. To achieve this, the specific objectives of the study are as follows:

• To understand the impact of temperature and exercise on limb blood flow in man
• To identify the relationship level between exercise activities, temperature, and limb blood flow in man

1.4 Research Questions

To address the objectives outlined above, the study will investigate the following research questions:

• What is the impact of temperature and exercise on limb blood flow in man?
• What is the relationship level between exercise activities, temperature, and limb blood flow in man?

 

1.5 Research Hypothesis

To achieve the study objectives, the following hypothesis was formulated:

Null Hypothesis (H0): H0: There is no relationship level between exercise activities, temperature, and limb blood flow in man

Alternative Hypothesis (H1): There is a relationship level between exercise activities, temperature, and limb blood flow in man

1.6 Significance of the Study

The findings of this research will contribute to the existing body of knowledge on the complex interplay between temperature, exercise, and limb blood flow. Understanding how temperature affects limb blood flow during exercise can have significant implications for athletes, exercise enthusiasts, and individuals working in extreme environmental conditions. The outcomes of this study may help optimize training protocols, develop strategies to prevent heat-related injuries and enhance performance in various athletic disciplines.

Furthermore, a comprehensive understanding of the physiological mechanisms underlying the relationship between temperature, exercise, and limb blood flow can have broader implications for vascular health. Abnormalities in limb blood flow regulation are associated with numerous vascular disorders, including peripheral artery disease and Raynaud’s disease. By elucidating these mechanisms, this research may contribute to the development of novel interventions and preventive measures for such conditions.

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