Sickle cell trait (SCT) can pose a grave risk for some athletes. In the past decade in NCAA Division I football, no deaths have occurred from the play or practice of the game, but 16 deaths have occurred from conditioning for the game, and 10 (63%) of these deaths are tied to SCT, an excess of up to 21-fold. Research shows how and why, during intense exercise bouts, sickle cells can accumulate and "logjam" blood vessels, causing explosive rhabdomyolysis that can kill. Sickling can begin in 2 to 5 min of all-out exertion and can reach grave levels soon thereafter if the athlete struggles on or is urged on by coaches despite warning signs. Sickling collapse is an intensity syndrome that differs from other common causes of collapse. Tailored precautions can prevent sickling collapse and enable athletes with SCT to thrive. Irrationally intense conditioning for a game puts the lives of healthy athletes with SCT at risk.

In brief How-and if-exercise alters immunity is open to debate. Research centers on changes in the number and function of granulocytes and lymphocytes and in levels of immunoglobulins. In general, these immune changes are mixed, mild, and brief. Clinical studies are inconclusive and fraught with confounders, especially the impact of psychological stress. Whether exercise enhances immunity or impairs it may, in fact, depend on whether the exercise is a joy or a stress.

1. Despite advances in the art and science of fluid balance, exertional heat illness -- even life-threatening heat stroke -- remains a threat for some athletes today. 2. Risk factors for heat illness include: being unacclimatized, unfit, or hypohydrated; certain illnesses or drugs; not drinking in long events; and a fast finishing pace. 3. Heat cramps typically occur in conditioned athletes who compete for hours in the sun. They can be prevented by increasing dietary salt and staying hydrated. 4. Early diagnosis of heat exhaustion can be vital. Early warning signs include: flushed face, hyperventilation, headache, dizziness, nausea, tingling arms, piloerection, chilliness, incoordination, and confusion. 5. Pitfalls in the diagnosis of heat illness include: confusion preventing self-diagnosis; the lack of trained spotters; rectal temperature not taken promptly; the problem of "seek not, find not;" and the mimicry of heat illness. 6. Heat stroke is a medical emergency. Mainstays of therapy include: emergency on-site cooling; intravenous fluids; treating hypoglycemia as needed; intravenous diazepam for seizures or severe cramping or shivering; and hospitalizing if response is slow or atypical. 7. The best treatment is prevention. Tips to avoiding heat illness include: rely not on thirst; drink on schedule; favor sports drinks; monitor weight; watch urine; shun caffeine and alcohol; key on meals for fluids and salt; stay cool when you can; and know the early warning signs of heat illness.

Overtraining refers to prolonged fatigue and reduced performance despite increased training. Its roots include muscle damage, cytokine actions, the acute phase response, improper nutrition, mood disturbances, and diverse consequences of stress hormone responses. The clinical features are varied, non-specific, anecdotal and legion. No single test is diagnostic. The best treatment is prevention, which means (1) balancing training and rest, (2) monitoring mood, fatigue, symptoms and performance, (3) reducing distress and (4) ensuring optimal nutrition, especially total energy and carbohydrate intake.

We studied the effect of serum folate-binding protein (FBP) on folate radioassays and the relationship of the serum level of unsaturated FBP to the serum folate level in various clinical states. Our modification of a heat-extracted radioassay was compared to a whole serum radioassay. Our results confirmed the existence of elevated serum levels of unsaturated FBP in some normal subjects, in some women taking oral contraceptives, and in most patients with uremia. Elevated levels of unsaturated FBP will produce falsely low results in folate radioassay unless the FBP has been destroyed by heat, as was done in the modified radioassay here presented. In normal and uremic subjects, serum folate and unsaturated FBP levels tended to correlate, whereas in patients taking large doses of folic acid the level of unsaturated FBP fell as the level of serum folate rose.

Exercise is a well-known stress test for uncovering heart or lung disease, but it can also stress other organs and unmask a range of medical disorders. Practical case examples are given in seven areas: anemia, headache, hematuria, gastrointestinal problems, seizure, anhidrosis, and hypothyroidism. Recognizing the exercise-induced manifestations can lead to timely diagnoses that improve and save lives.

A two-step infection by the Epstein-Barr virus accounts for the characteristic features of infectious mononucleosis (IM). New serologic tests for viral antigens exist, but a rapid kit test for heterophil antibody usually suffices to confirm the diagnosis. General management is supportive only. Splenic rupture is very rare, almost never fatal if diagnosed early, and, in most cases, is probably best treated by splenectomy. Athletes tend to recover from IM faster than nonathletes. When the spleen returns to normal size, the athlete can return to contact sports, though it may take 3 to 6 months for an elite athlete to regain top form.

No abstract