Sports syncope is a sudden, transient loss of consciousness, loss of muscle tone with fall caused by a momentary lack of blood supply to the brain or changes in blood chemicals during or after exercise. These include vascular decompression syncope, gravitational shock syncope, postural hypotensive syncope, episodic muscle weakness, primary loss of consciousness and other types.
A. Classification of motor syncope
1.Vascular decompression syncope
Also known as vagal reflex syncope or simple syncope, its incidence accounts for the first of all types of syncope. Mood swings, mental stimulation or competition injuries and other factors can induce transient vasodilation through the vagal reflex, resulting in a decrease in the amount of cardiac blood return and cardiac output, a drop in blood pressure, insufficient blood supply to the brain, and syncope, which is usually seen in athletes who are younger or less experienced in competition, and is more common in women. This type of syncope occurs when athletes are recovering from injury, overexerting themselves, or suddenly participating in high-intensity training or competition after a break in training. The prodromal symptoms include dizziness, sweating, nausea, pallor, limb weakness, etc. The above symptoms last for tens of seconds to minutes before LOC occurs, and can awaken on its own after a few seconds to tens of seconds. There is no organic disease on physical examination and no sequelae.
2.Gravitational shock syncope
When an athlete performs lower extremity-based exercise, the lower extremity muscle oxygen consumption increases and capillaries dilate, so if there is an abrupt stop after strenuous exercise, a large amount of blood will pool in the lower extremity blood vessels and the cerebral blood supply will be insufficient, triggering syncope, mostly seen in track and field events. Precursory symptoms include dizziness, weakness, nausea, pallor, cold extremities, and in severe cases, fainting.
3.Postural hypotensive syncope
When the horizontal position suddenly changes to upright position, the muscle pump function and vascular regulation dysfunction can lead to blood pooling in the lower extremities, resulting in transient cerebral ischemia, which mostly occurs after swimming competitions. Sudden onset of LOC, no antecedent symptoms.
4.Episodic muscle weakness
Also known as sudden onset weakness, it refers to sudden collapse due to temporary damage to the anti-gravity extensor muscles of the extremities caused by a lowering of the response threshold of the central nervous system, mostly seen in rowing competitions. The athlete appears weak and weak a few minutes after completing the race, followed by syncope, which lasts for a short time, only a few seconds.
5.Primary loss of consciousness
Syncope due to hypoxia and hypocapnia of the brain cadre reticular tissue caused by abnormal nerve conduction direction, often occurs after intense competition and high-intensity training, such as long-distance racing. The onset is accompanied by blurred consciousness, deeper LOC, longer duration of syncope, inability to remember the last moments of the race after waking up, and may be accompanied by neurological symptoms such as aphasia after awakening.
6. Syncope due to hyperventilation syndrome
Due to excessive respiration or shortness of breath, excessive carbon dioxide discharge from the body can lead to respiratory alkalosis, which causes cerebral capillary constriction, ischemia and hypoxia of brain cells, and even syncope. In diving and swimming before the preparation for the closure of the air and take hyperventilation, can cause syncope, which is the main reason for the drowning of athletes.
7, hypoglycemic syncope
The more common type of sports syncope, mostly seen in long-distance sports. People with a history of hypoglycemia are prone to induce hypoglycemia during exercise. Precursory symptoms include hunger, weakness, sweating, dizziness, tachycardia, and confusion, etc. Consciousness can be restored quickly after glucose supplementation.
8.Cardiogenic syncope
Cardiogenic syncope is a dangerous but common type of syncope caused by various heart diseases (such as hypertrophic cardiomyopathy, coronary artery malformation, coronary artery disease, myocarditis, heart valve disease, Marfan syndrome, sinus node artery stenosis, pre-excitation syndrome, long QT syndrome, arrhythmogenic right ventricular cardiomyopathy, etc.), followed by cerebral hypoxia and syncope, which can be seen in soccer, basketball, cycling, tennis, ice hockey, marathon, etc. It can be seen in football, basketball, cycling, tennis, ice hockey, marathon, etc.
9.Brain-derived syncope
The syncope occurs when the cerebral blood vessels are extensively ischemic during sports, and is seen in athletes and coaches who suffer from cerebrovascular congenital malformation, atherosclerosis, hypertension and cervical spondylosis. The attack is mostly accompanied by headache, vertigo, vomiting, and sometimes aphasia, mild hemiparesis and vision loss.
10, heatstroke fainting
The body produces more heat during exercise, and due to the high temperature of the external environment, the body’s thermoregulatory ability decreases, resulting in elevated body temperature and multi-organ dysfunction, especially central nervous system dysfunction; in addition, massive sweating and dehydration, water and electrolyte imbalance in the body and reduced blood volume can also lead to syncope. The disease mostly occurs in high temperature and high humidity environments, and is mostly seen in long-distance running, marathon, cross-country running, cycling and soccer. Athletes are prone to dizziness, headache, chest tightness, thirst, nausea, vomiting, tachycardia and muscle cramps when training and competing in the summer, and if cooling measures are not taken, syncope or even death can occur.
11, fainting due to increased pressure in the chest and lungs
Weight lifting process due to prolonged breath-holding force to increase thoracic pressure, left ventricular filling impairment, blood pressure drop, cerebral blood flow reduction, and then a transient syncope.
Second, the treatment of sports syncope
Patients with syncope should be treated actively for different causes. Once the preliminary symptoms of syncope appear during exercise, that is, with the help of others, jogging or walking slowly for a distance, and then lying down for a while to wait for the body to gradually recover.
1.General treatment
Syncope take supine, lower limbs elevated position to increase cerebral blood flow, while loosening the collar and trouser belt, turn the head to the side. If necessary, give oxygen, and acupressure or acupuncture points such as Renzhong, Yongquan and Hegu or sniff ammonia. Vascular decompression syncope, postural hypotensive syncope, episodic muscle weakness, and primary LOC can generally be relieved after receiving the above treatments.
2.Etiology treatment
In diving and swimming, the time between the occurrence of LOC and death generally does not exceed 2.5 minutes, so it should be quickly resuscitated.
(1) Hypoglycemic syncope: intravenous injection of 50% glucose 60ml.
(2) Cardiogenic syncope: Immediately administer oxygen, give anti-arrhythmic, anti-shock or anti-heart failure treatment according to the cause, and promptly transfer to hospital.
(3) Cerebral syncope: administer oxygen, keep the airway open, lower the cranial pressure, etc., and then transfer to the hospital.
(4) Heatstroke syncope: move the patient to a cool and ventilated place quickly and give physical cooling.