Macronutrients in Exercise

liver

glucose, amino acids, and fatty acids must pass through the liver;

fuel molecules released by other tissues must travel to the liver for additional processing

major fuel sources for the muscle

fatty acids and glucose; can also use ketone bodies

adipose tissue

stores TAG, energy reservoir for the body, releases fatty acids

primary energy source for the brain and nerve cells

glucose

energy source for red blood cells

relies exclusively on glucose under all metabolic conditions

kidneys

require 10% of total energy, produce urine and remove metabolic waste

What state is most similar to endurance exercise lasting between 30-90 minutes?

the post-absorptive state

In which state are amino acids primarily used for gluconeogenesis?

the fasting state

In which state does glycerol become that major source for gluconeogenesis?

starvation state

In which state are fatty acids used to greater extent in an effort to spare protein?

starvation state

What state is the equivalent of running 3 ½ to 4 hours without fuel?

starvation state

Which hormones increase during exercise?

epinephrine, cortisol, and growth hormone

What processes do epinephrine, cortisol and growth hormone increase?

gluconeogenesis, glycogenolysis, lipolysis

Levels of what increase in the bloodstream during exercise?

fatty acids and glucose

What happens to the endocrine hormones if not fed during extended exercise (>90 minutes)?

insuline drops

glucagon increases to promote plasma glucose availability

epinephrine and cortisol increase dramatically to promote fatty acids use after 90 minutes

How can you prevent regulatory hormone spikes during extended exercise?

providing carbohydrate during exercise

ATP-phosphocreatine system

uses high-energy phosphate bonds of phosphocreatine to quickly regenerate ATP, no O2 required

used for high intensity, short duration exercise; only lasts 10-25 seconds

lactic acid (anaerobic) system

uses the glycolytic pathways without O2 to produce ATP, incomplete breakdown of one molecule of glucose into two molecules of lactate

inefficient and only used in the short-term due to lactate build up which increases cell pH and causes pain and fatigue

oxidative (aerobic) system

requires O2, but is able to completely catabolize glucose, FAs, and some AAs -most efficient ATP production

primary system for endurance events/high energy capacity, low power sports

CHO predominate energy source up to 20 minutes then FAs start to kick in

Primary fuel source during low intensity exercises

fat

primary fuel source during high intensity exercise

muscle glycogen

Describe carbohydrate loading (modified)

Days 0-2: 50% CHO

Days 3-6: 70% CHO

Tapering exercise: 90, 40, 40, 20, 20 min, rest

Type 1: slow twitch muscle

endurance muscles, high in mitochondria, hemoglobin, iron, and oxygen

red muscle

aerobic (oxidative) energy system

Type 2: Fast twitch muscles

sprinting muscles-quick burst, short duration

relies on glycolytic pathway and the anaerobic/lactic acid system fewer mitochondria, low hemoglobin and low O2 delivery

white muscle