Human and Animal Sleep Rhythms, and Alertness: Hunters should adjust their internal awake fullness clock to maximum success. The human body begins to enter sleep in response to increased melatonin, which is released by the hypothalamus gland, which is governed by decreasing sunlight. In a natural world life, circadian rhythms would be controlled by sun light. However, we human have altered our rhythms through use of artificial light. We stay up later and arise earlier. More importantly for hunters, people whose circadian sleep cycles are controlled by artificial light do not see melatonin blood levels recede to daytime levels until for an hour or so. That means these hunters are still mentally awakening and not at full cognitive capacity. So what happens when hunters go afield and have to adjust to natural sleep patterns? Dr. Kenneth P. Wright is Director of the Sleep and Chronobiology Laboratory, University of Colorado. He made a study of eight healthy (biologically normal) adults who wore electronic “activigraph” monitors for a week. Then the group went camping for a week. Absolutely no artificial light was allowed while camping. There was just sunlight, moonlight and stars. The study found that with as short a time as a week, the campers had adjusted their biologic melatonin release sleep/awake cycles to nearly perfect synchronization with sunset. The importance to hunters is that the decrease in melatonin occurred an hour earlier in the morning. (See Book recorded example of a heartbeat morning slow increase.) Isn’t that when hunters should go afield totally alert to encounter AND BE TOTALLY COGNIZANT of all forest conditions? Now consider that nocturnal animals wake up with the sunset and increasing melatonin. The game slowly enters activity periods. Hunters should do their utmost to keep vigilant during dusk. Conversely, heavily overcast days will cause animals to arise from day beds earlier, so get to your stand and well settled earlier in the afternoon than normal. Dreams of Suffocation and Hallucinations: Be prepared for some different sleep effects. Many people have vivid dreams or feelings of being gagged or suffocated. Hallucinations may occur between the sleep to wakefulness transition. You may experience Cheyne Stokes Syndrome (periodic breathing rate changes) at higher altitudes. This is a form of sleep apnea. A person takes several deep breaths followed by shallow breathing. Typically, there may be 5-15 seconds of no breathing. During the shallow/no-breathing phase, the body’s oxygen level drops. The pituitary gland and heart electrical nodes send signals to increase oxygen, resulting in a deep, fast lung breathing reaction. The low oxygen level induces sleep arousals. You therefore will not get enough long-period deep sleep (REM). Mornings will find you “groggy” and tired. Practice deep breathing when you awaken at night or during the day. It quickly lowers the blood carbon dioxide level and increases blood oxygen concentration. Sleep Warning: Never go to higher altitudes in the wilderness to sleep if you are already experiencing any kind of altitude sickness. Wait to see if you acclimate, or the condition gets worse and you must leave. Please see the webpage sections on adjusting to high altitudes and the effects of poor sleep on hunting success. Hunters May be Affected by the Moon (But may not Realize It): Do you think you are always truly attentive? Notice the full moon in the photograph? Elk and deer (and probably all animals) behave