question: If Digestion Takes 6-8 Hours How Do People Experience Diarhea Symptoms in Hours?
comment: Diarrhea happens precisely because digestion *hasn't* happened yet. Yes, normally it takes hours for food to make its way through your stomach and intestines to slowly absorb water and nutrients, but diarrhea is bypassing all that. Your gut has a ton of nerves, and when it senses something is amiss for any reason, it triggers your brain to send signals to get whatever is causing the situation out as quickly as possible. That means there's little to no absorption of water or nutrients. In fact, the intestines can actually add water or mucus to get things flowing even faster.
passages: Section::::Symptoms.
  
  The average incubation periods for giardiasis and cryptosporidiosis are each 7 days. Certain other bacterial and viral agents have shorter incubation periods, although hepatitis may take weeks to manifest itself. The onset usually occurs within the first week of return from the field, but may also occur at any time while hiking.
   Section::::Motility.:Contraction patterns.
  
  The patterns of GI contraction as a whole can be divided into two distinct patterns, peristalsis and segmentation. Occurring between meals, the migrating motor complex is a series of peristaltic wave cycles in distinct phases starting with relaxation, followed by an increasing level of activity to a peak level of peristaltic activity lasting for 5–15 minutes.
  
  This cycle repeats every 1.5–2 hours but is interrupted by food ingestion. The role of this process is likely to clean excess bacteria and food from the digestive system.
  
  Section::::Motility.:Contraction patterns.:Peristalsis.
   It may be difficult to associate a particular case of diarrhea with a recent wilderness trip of a few days because incubation of the disease may outlast the trip. Studies of trips that are much longer than the average incubation period, e.g. a week for "Cryptosporidium" and "Giardia", are less susceptible to these errors since there is enough time for the diarrhea to occur during the trip. Other bacterial and viral agents have shorter incubation periods, although hepatitis may require weeks.
   Diarrhea is most commonly caused by a myriad of viral infections but is also often the result of bacterial toxins and sometimes even infection. In sanitary living conditions and with ample food and water available, an otherwise healthy patient typically recovers from the common viral infections in a few days and at most a week. However, for ill or malnourished individuals diarrhea can lead to severe dehydration and can become life-threatening without treatment.
  
  Section::::Diseases and conditions.:Constipation.
   Section::::Human gastrointestinal tract.:Function.
  
  The time taken for food or other ingested objects to transit through the gastrointestinal tract varies depending on many factors, but roughly, it takes less than an hour after a meal for 50% of stomach contents to empty into the intestines while total emptying takes around 2 hours. Subsequently, 50% emptying of the small intestine takes between 1 and 2 hours. Finally, transit through the colon takes 12 to 50 hours with wide variation between individuals.
  
  Section::::Human gastrointestinal tract.:Function.:Immune function.
  
  Section::::Human gastrointestinal tract.:Function.:Immune function.:Immune barrier.
   In acute disease, explosive diarrhea may occur as often as every twenty minutes. Perforation of the colon may also occur in acute infections which can lead to life-threatening situations.
  
  Section::::Life cycle.
  
  Infection occurs when a host ingests a cyst, which usually happens during the consumption of contaminated water or food. Once the cyst is ingested, it passes through the host’s digestive system.
   The onset of TD usually occurs within the first week of travel, but may occur at any time while traveling, and even after returning home, depending on the incubation period of the infectious agent. Bacterial TD typically begins abruptly, but "Cryptosporidium" may incubate for seven days, and "Giardia" for 14 days or more, before symptoms develop. Typically, a traveler experiences four to five loose or watery bowel movements each day. Other commonly associated symptoms are abdominal cramping, bloating, fever, and malaise. Appetite may decrease significantly. Though unpleasant, most cases of TD are mild, and resolve in a few days without medical intervention.
   During digestion, food is stored in the liquid present in the stomach. The food that is not digested travels to the large intestine and colon in liquid form. These organs begin to absorb the water turning the food into a more solid form. Different viruses or bacteria can increase the amount of liquid that is secreted and moves too quickly through the digestive tract for the water to be absorbed. Diarrhea comes in two types: acute diarrhea and chronic diarrhea. The acute diagnosis can last for a few days up to a week of time. Chronic diarrhea lasts for several days or longer periods of time lasting a few weeks. The difference in diagnosis will help determine the cause of the illness.
   The human gastrointestinal tract is around 9 meters long. Food digestion physiology varies between individuals and upon other factors such as the characteristics of the food and size of the meal, and the process of digestion normally takes between 24 and 72 hours.
   Humans ingest the metacercaria either by the infected fish or contaminated vegetable. The parasite travels through the digestive tract into the duodenum, then continues down to reach the cæcum, where it self-fertilizes and lay eggs, continuing the cycle.
  
  Heavy infection in humans is suspected to cause diarrhœa, fever, abdominal pain, colic, malnutrition, anæmia, and even death.
  
  Section::::Pathogenicity and pathology.
   Section::::Role in disease.:Incubation period.
  
  The time between ingesting the STEC bacteria and feeling sick is called the "incubation period". The incubation period is usually 3–4 days after the exposure, but may be as short as 1 day or as long as 10 days. The symptoms often begin slowly with mild belly pain or non-bloody diarrhea that worsens over several days. HUS, if it occurs, develops an average 7 days after the first symptoms, when the diarrhea is improving.
  
  Section::::Role in disease.:Treatment.
   Symptoms can begin to manifest at any point from the ingestion of the meal to 120 minutes thereafter. However, the more common range is between 30 seconds to 1 hour after the completion of a meal. Symptoms tend to cease when the ruminated contents become acidic.
   Immediately after the surgery is complete, the patient tends to pass liquid stool with frequent urgency, and he or she may have 8 to 15 bowel movements per day, but this eventually decreases with time. Because the ileo-anal pouch is a considerably smaller reservoir than the colon, patients tend to have more frequent bowel motions; typically 6-8 times a day. Also because the ileum does not absorb as much water as the colon, the stools tend to be less formed, and sometimes fluid. The normal pouch output is described to be of a consistency similar to porridge. People who find that the consistency remains loose or who experience bowel movements too frequently usually take loperamide or codeine phosphate to thicken the stool and slow the bowel movement.
   Another patient, in whom POIS was suspected to be caused by cytokine release, was successfully treated with nonsteroidal anti-inflammatory drugs (NSAIDs) just prior to and for a day or two after ejaculation. The patient took diclofenac 75 mg 1 to 2 hours prior to sexual activity with orgasm, and continued twice daily for 24 to 48 hours.
   Section::::Treatment.:Antibiotics.
  
  If diarrhea becomes severe (typically defined as three or more loose stools in an eight-hour period), especially if associated with nausea, vomiting, abdominal cramps, fever, or blood in stools, medical treatment should be sought. Such patients may benefit from antimicrobial therapy. A 2000 literature review found that antibiotic treatment shortens the duration and severity of TD; most reported side effects were minor, or resolved on stopping the antibiotic.
   Transmission is via the fecal–oral route, and most illness has been through distribution of contaminated raw leaf green vegetables, undercooked meat and raw milk.
  
  Section::::Signs and symptoms.
  
  "E. coli" O157:H7 infection often causes severe, acute hemorrhagic diarrhea (although nonhemorrhagic diarrhea is also possible) and abdominal cramps. Usually little or no fever is present, and the illness resolves in 5 to 10 days. It can also sometimes be asymptomatic.
   In volunteer studies with infected beef, symptoms appeared 3–6 hours after eating. These included anorexia, nausea, abdominal pain, distension, diarrhea, vomiting, dyspnea, and tachycardia. All symptoms were transient and lasted about 36 hours. In a second series, symptoms — abdominal pain, distension, watery diarrhea, and eosinophilia — appeared at 1 week and resolved after 3 weeks.
  
  Clinical cases have been associated with acute fever, myalgias, bronchospasm, pruritic rashes, lymphadenopathy, subcutaneous nodules associated with eosinophilia, elevated erythrocyte sedimentation rate, and elevated creatinine kinase levels. Symptoms may last as long as five years. Segmental necrotizing enteritis has been reported on one occasion.
   Dysentery caused by EIEC usually occurs within 12 to 72 hours following the ingestion of contaminated food. The illness is characterized by abdominal cramps, diarrhea, vomiting, fever, chills, and a generalized malaise. Dysentery caused by this organism is generally self-limiting with no known complications.
  
  Enterovirulent classes of "E. coli" are referred to as the EEC group (enterovirulent "E. coli"):
  
  BULLET::::1. Enteroinvasive "E. coli" (EIEC) invades (passes into) the intestinal wall to produce severe diarrhea.
  
  BULLET::::2. Enterohemorrhagic "E. coli" (EHEC): A type of EHEC, "E. coli" O157:H7, can cause bloody diarrhea and hemolytic uremic syndrome (anemia and kidney failure).
   Precautions that are likely to help prevent gastric dilatation-volvulus include feeding small meals throughout the day instead of one big meal and not exercising immediately before or after a meal.
  
  Section::::Prognosis.
  
  Immediate treatment is the most important factor in a favorable prognosis. A delay in treatment greater than six hours or the presence of peritonitis, sepsis, hypotension, or disseminated intravascular coagulation are negative prognostic indicators.
   Pre-surgery NPO orders are typically between 6 and 12 hours prior to surgery, through recovery suite discharge, but may be longer if long acting medications or oral post-meds were administered. It is not uncommon for the food NPO period to be longer than that for liquid, as the American Board of Anesthesiology advises against liquid NPO periods greater than eight hours. The NPO periods for illness tend to be much longer, although exceptions are made for small scheduled amounts of water consumption if an IV drip is not in use. With sufficient IV fluids, NPO periods of several days have been utilized successfully in non-diabetic patients (although short NPO periods in diabetics are possible with IV fluids, insulin, and dextrose. Extended periods (greater than 12 hours) are still contraindicated.
   Gastroenteritis usually involves both diarrhea and vomiting. Sometimes, only one or the other is present. This may be accompanied by abdominal cramps. Signs and symptoms usually begin 12–72 hours after contracting the infectious agent. If due to a virus, the condition usually resolves within one week. Some viral infections also involve fever, fatigue, headache and muscle pain. If the stool is bloody, the cause is less likely to be viral and more likely to be bacterial. Some bacterial infections cause severe abdominal pain and may persist for several weeks.
   Occasionally, gastroesophageal reflux (GERD) may be associated with delayed gastric emptying of solids, but clear liquids are not affected. Raised intra-abdominal pressure (e.g. in pregnancy or obesity) predisposes to regurgitation. Certain drugs such as opiates can cause marked delays in gastric emptying, as can trauma, which can be determined by certain indicators such as normal bowel sounds and patient hunger.
  
  Section::::Minimum fasting times.
   The long incubation period of many foodborne illnesses tends to cause sufferers to attribute their symptoms to gastroenteritis.
  
  During the incubation period, microbes pass through the stomach into the intestine, attach to the cells lining the intestinal walls, and begin to multiply there. Some types of microbes stay in the intestine, some produce a toxin that is absorbed into the bloodstream, and some can directly invade the deeper body tissues. The symptoms produced depend on the type of microbe.
  
  Section::::Mechanism.:Infectious dose.
   This may be partially due to the unusually slow rate of digestion apparent in lancetfish, where actual digestion seemingly does not begin in earnest until the beginning of the small intestines.
   Gastroparesis (delayed gastric emptying) may occur and is due to metabolic causes (e.g. poorly controlled diabetes mellitus), decreased gastric motility (e.g. due to head injury) or pyloric obstruction (e.g. pyloric stenosis). Delayed gastric emptying usually only affects the emptying of the stomach of high-cellulose foods such as vegetables. Gastric emptying of clear fluids such as water or black coffee is only affected in highly progressed delayed gastric emptying.
  