I have a question. When I was in exercise phys lab we did anaerobic tests. After these test some of the untrained people in the class would pass out after the test. I know why they passed out but i cant for the life of me remember the term used for it. Can anybody help me? Ive looked in my phys book and i cant find it anywhere and its driving me crazy.

I belive that you are talking about the Valsalva effect.

I second Doug’s thought. This is why we make sure hypertensive clients don’t hold their breath during resistance exercise. The valsalva maneuver can also very easily aggravate and existing hernia.

I dont think thats the term im thinking of though it very well might be. It was caused when lactate acted as a vasodilator and caused blood to pool in the lower extremeties. thus limiting blood to the brain. Our teacher would lie them on their backs and lift their legs and you could actually see the blood flowing back toward their upper body. Im going to go ask him as soon as school gets back in but id love to be able to remember it.

Vasovagal response

Vasovagal response - unwanted, but realistic in lifters.
This is from the American Academy of Family Physicians:
Vasovagal syncope is characterized by the common faint, resulting from “vagally” mediated cardioinhibition. The resulting bradycardia reduces cerebral blood flow to a level inadequate to maintain consciousness. Because of the episodic nature of vasovagal syncope and the heterogeneity of the patient population, it is difficult to make specific therapy recommendations. Fenton and associates reviewed the current understanding of vasovagal syncope to provide a diagnostic and therapeutic approach.

The vagus nerve transmits afferent signals from the aortic arch baroreceptors, regulating arterial pressure. Increases in arterial flow stimulate efferent vagal outflow, inhibiting sympathetic drive and decreasing blood pressure. Assumption of an upright position with pooling of blood in the lower extremities activates this autonomic cycle and results in increased sympathetic tone to the vasculature and heart, causing vasoconstriction, increased heart rate and maintenance of blood pressure.

The vasovagal response is caused by excessive venous pooling that paradoxically results in vasodilatation and bradycardia rather than the appropriate physiologic responses of vasoconstriction and tachycardia. Other modulating factors that may be present during syncope include serotonin, adenosine and opioids. Nitric oxide has also been implicated in the vasodilatory response associated with vasovagal syncope.

Vasovagal syncope usually has a gradual onset, although sudden loss of consciousness without warning can occur. Precipitating factors may be the sight of blood, a loss of blood, sudden stress or pain, surgical manipulation or trauma. Before the syncopal event, the patient may report weakness, lightheadedness, yawning, nausea, diaphoresis, hyperventilation, blurred vision or impaired hearing. Sitting or lying down may abort the syncopal episode.

There are no specific physical signs related to vasovagal syncope. Tilt-table testing provokes venous pooling and resultant vasovagal syncope. Pharmacologic agents used to emphasize this effect are not well standardized. Testing is warranted in patients whose syncope is uncertain to be vasovagal and in patients with one or more of the following indications: (1) recurrent syncope, (2) a single syncope episode associated with injury, (3) a single syncope episode associated with a high-risk setting, or (4) syncope of another established cause whose treatment might be affected by vasovagal syncope. Head-up tilt-table testing is contraindicated in patients with critical obstructive cardiac disease (such as critical proximal coronary artery stenosis, critical mitral stenosis or severe left ventricular outflow obstruction) or critical cerebrovascular stenosis.

Treatment is empiric because the specific physiologic triggers of vasovagal syncope are largely unidentified. Infrequent episodes require only counseling and observation. Hydration and salt intake may need to be increased, especially in warm weather. Pharmacologic treatment options include beta-adrenergic blockers, anticholinergic agents, adenosine receptor blockers, selective serotonin reuptake inhibitors, mineralocorticoids and anticonvulsants. The use of compression hose and pacemakers has been recommended.

The term is “orthostatic hypotension”.

Doug thank you so much. I was just missing the syncope to make it sound right in my head. I really appreciate your thorough response.

Thanks. The question made me think a bit, I like that!

Hey Goldberg, I was in your class, I was one of those people who almost passed out, infact the only one at that time and, but I was far from being untrained. Infact I had just come off of “marathon” cardio where I had been doing over 15plus hours per week. I asked Dr.M and he said it was because I didnt have enough food in my system. Glad you turned me on to this site man. See you in class bro.

Cardio has nothing to do with it. It has to do with the ability to clear lactate. Cardio doesnt generate much lactate so that type of training wouldnt have an effect on clearance. I felt no effects from the test. I believe it is because i was used to pushing myself through heavy squats and deadlifts when i was bursting with lactate. Im sure that helped my clearance rate. Glad you found the site.

I would have to disagree that your cardiovascular conditioning has nothing to do with orthostatic tolerance. People who are aerobically trained have dense capillarization in the muscle which can be opened up with intense exercise, especially when a lot of H+ ions are floating around from the lactic acid production. If the person immediately stops or slows down too much after an anaerobic test, then you lose the skeletal muscle pump which pumps blood back up the body from the legs to the heart. When losing the skeletal muscle pump, a trained person will have more vasculature in the lower body for the blood to pool because of two reasons. First, they have more total capillaries as compared to an untrained person and second, because they can produce more H+ ions due to a high state of training. Therefore, a trained person has more vascular beds to open overall and more of an ability to produce the metabolites (H+, nitric oxide, CO2) that open those beds.

that is true but my only point was with lactate levels. they arent normally jacked when training in the “fat burning” zone so you wont be trained to clear it. Ive read that trained athletes have better ability to clear lactate following training. these benefits might not be seen in pure aerobic training.

Goldberg - It is true that most recreational aerobic athletes who spend time in the so called “fat-burning” zone may not be used to a lot of lactate, but those that are serious trainers can spend a lot of time above the lactate threshold both producing more and clearing more. People’s response to a maximal anaerobic test will clearly be different depending on what kind of training level they attain.

You are right. Someone who trains for endurance at a high level will train above the lactate threshold. But ive seen William T train and i dont think he was at that level. No offense to him. I know if i push myself at all on aerobic exercise i generate lactate like crazy. I dont believe there is any fat burning zone for me. I can “feel the burn” just walking up stairs. Im definitely a fast twitch person. Although running a 2 1/2 minute cheerleading rountine everyday for the past two months has definitely increased my work capacity. Try doing 12 100lb kettlebell snatches with a kettlebell that moves a different way everytime. Oh yeah. do a back flip somewhere in the middle of all that. WHEW! One more week to nationals. I cant wait. This time next week i should be a national champion!

Good luck at Nationals and thanks for the discussion.