Recovery

A Nocturnal Wake-up Call For All Athletes

The relationship between the energy or fuel status of the liver and the quality and duration of restorative sleep is one of the most neglected areas of human physiology. Chronic nocturnal metabolic stress can be easily prevented by simply providing adequate fuel for the liver during the night fast. The modern myth about not eating before bedtime contributes to this failure to restock the critical liver storehouse with glycogen. The ultimate outcome from months and years of neglect in providing fuel for the liver and hence the brain during sleep contributes to a rising tide of related metabolic disorders associated with poor quality sleep. These disorders include childhood and adult obesity, type 2 diabetes, hypertension and cardiovascular disease, immune system malfunction, gastric ulcers and other gastrointestinal disorders, infertility, depression, memory loss, dementias and Alzheimer’s disease.

All of these conditions are directly connected to poor liver glycogen status. As the liver supply of glycogen reaches low levels, the “stress” protein IGFBP-1 is released to warn the brain of low fuel status. Insulin-like growth factor-1 (IGF-1) is inhibited and cellular death, rather than cell restoration and recovery, progresses unabated. The brain releases other stress hormones, cortisol and adrenalin in order to produce glucose from muscle protein and insure adequate brain fuel supply. Cortisol is the key hormone associated with metabolic stress.

Another fascinating recent discovery in this unfolding narrative links IGF-1 to an enzyme known as 11 Beta Hydroxy Steroid Dehydrogenase-1 (11BetaHSD-1). This enzyme is found in the liver, adipose (fat) tissue, brain and muscle, the organs and tissues intimately involved in energy homeostasis. It acts in each of these tissues to activate cortisol from its inactive form cortisone. 11BetaHSD-1 has been found to be active in producing intracellular cortisol in conditions of the metabolic syndrome, even when serum cortisol levels are normal. When IGF-1 is inhibited, 11BetaHSD-1 levels are elevated resulting in activation of cortisol within the cells. This intracellular stress would be “hidden” and not apparent from circulating cortisol levels.

This link completes the model for understanding the relationship between liver glucose metabolism, peripheral glucose metabolism in muscle, and the cascade of conditions known as the metabolic syndrome. When liver glycogen is low, IGF-1 is inhibited, intracellular 11BetaHSD-1 activates cortisol which in turn inhibits glucose metabolism and disposal in the peripheral tissues. As intracellular glucose levels become elevated, fat metabolism and disposal is also inhibited due to the inhibition of the fat transporter, CPT, giving additional explanation for the consequences of the metabolic syndrome. It seems counterintuitive that low levels of glucose in the liver affect metabolism of fats in muscle and contribute to obesity and diabetes, but the connections are clear.

Sleep is an energy driven physiologic process. Regulation of sleep energy status is controlled by the SCN and the hypocretins produced in response to light/dark cycles. When a low energy status or low energy supply in the liver threatens normal brain functioning, the process does not simply shut down as when an automobile runs out of gas. Rather a whole host of activities is initiated by way of hormonal release and/or intracellular activation of cortisol by 11BetaHSD-1. This cascade of activity impairs quality sleep and results in metabolic stress that over time results in the conditions referred to as the metabolic syndrome.

Natural honey when ingested prior to bedtime will optimally refuel the liver and promote quality sleep. Recovery physiology during the night fast is insured and promoted. Metabolic stress is prevented. Memory processing during REM sleep occurs naturally and leads to improved learning. Honey is an inexpensive, non-pharmacological, revolutionary solution that optimizes human physiology during the periods of our normal circadian rhythms. A tablespoon of natural honey ingested prior to bedtime replenishes liver glycogen and modulates the first cascading pathway illustrated below in favor of recovery, restful, restorative, metabolically beneficial sleep. Without optimum liver glycogen, the second cascade prevails resulting in metabolic stress and its multiple associated conditions.

Liver Fuel Status Summarized

Cascade from Liver Glycogen to Restorative Sleep

Normal or high liver glycogen levels insure

High levels of free IGF-1 which cause

Levels of the enzyme 11BetaHDS-1 to remain low keeping

Cortisone inactive which results in

Lowered metabolic stress allowing

Restorative sleep and recovery to occur

Metabolic Stress Cascade

Low liver glycogen levels trigger the production and release of

Elevated levels of IGFBP-1 which are associated with

Elevated levels of the enzyme 11BetaHSD-1 which

Activate intracellular cortisone producing

Increased metabolic stress resulting in

Poor quality sleep and a

Myriad of conditions known as
The Metabolic Syndrome

(c) Mike McInnes and Ron Fessenden MD MPH May 28th 08