The Science Of Vasodilation

Saturday, March 16, 2019

For people who are training for body building, weight lifting or who are athletes, apart from a muscular physique and lower body fat%, what else is important is a higher vasculature. When you compare two bodybuilders with exact same height, weight, muscle mass, fat mass still one with higher vascularity will have an edge over the other. Sight of veins pumping out gives a higher aesthetic appeal. Apart from genetics, there are many factors that result in higher vascularity. This article digs deep in the science of vasodilation and the factors that attenuate vasodilation.

What Is Vasodilation?

Vasodilation is the widening of the blood vessels that results from the relaxation of smooth muscles and reduction in blood pressure. Vasodilation occurs when your blood vessels expand, which allows larger amounts of oxygen and nutrient rich blood to reach muscles. You can workout with better endurance and power. Muscle fatigue is lesser when muscles are fuelled with nutrients and water.

Mechanism Of Vasodilation

Arteries are large blood vessels that carry blood away from the heart, towards tissues. Whereas, Veins are smaller blood vessels that pump blood towards heart. Venous flow is slower than arterial flow of blood, which causes build-up of blood and increases the venous pressure. Also, muscle has “residual tension at rest,” which provides some resistance against venous return. Your veins carry blood to the heart, and when you exercise, the increase in blood flow creates a blood backup in your veins, creating higher blood pressure. That compresses the returning veins and causes the blood to build up and engorge the veins at the skin surface. The more muscle you have, the more residual tension at rest, which means your veins are more dilated.

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the-science-of-vasodilation-image

Citrulline Supplement

  • Factors Known To Increase Vasodilation
  • Increased Muscle mass
  • Decreased subcutaneous fat
  • Decreased water retention prior to weightlifting competition for better vascular appearance
  • Use of heat – gives a temporary superficial ramified veins.
  • One of the best known mechanisms for inducing Vasodilation is by Nitric oxide (NO).
  • Nitric oxide is produced within the body and is a natural vasodilator.

Ways to increase Nitric oxide

  • Having foods rich in nitrates like Beetroot, lettuce, carrots, parsley, cabbage, radishes, spinach, celery certainly increases NO levels and induces vasodilation. Nitrates in foods like beetroot, spinach and lettuce get converted to nitrites by saliva in mouth which then is converted to nitric oxide by gastric enzymes. Nitric oxide then relaxes the blood vessels and causes vasodilation
  • Flavonoids naturally present in foods like broccoli, spinach, dark chocolate – increase the activity of enzyme nitric oxide synthase. This enzyme is responsible for formation of nitric oxide.
  • Also nuts like pistachios, Onion that is rich in quercetin all help boost nitric oxide naturally
  • L- Arginine is a semiessential amino acid found in foods like eggs, red meat, chicken , cheese, milk, almonds is researched to increase nitric oxide production.
  • Citrulline - L-Citrulline (Cit) is a naturally occurring nonessential amino acid, present in mammals and also in every living organism. It is produced by the body naturally. About 80% of Cit is converted in the kidney to arginine (Arg), finally converting/recycling Arg to Cit and NO and serving as a potent Arg precursor.
  • Citrulline is also available as supplement – in the form of Citrulline Malate (salt of malic acid)
  • Sources of Citrulline- found naturally in certain foods such as watermelons, cucumbers, pumpkins, muskmelons, bitter melons, squashes, and gourds.

Arginine Or Citrulline ?

Research has shown that Citrulline supplementation has better result on Nitric oxide (NO) signalling as compared to Arginine (ARG) supplementation. A German study has proven this. Equal amounts of Arginine and Citrulline were given to 2 batches, Later batch produced a greater NO level as compared to Arginine batch. It was concluded that 3 gm dose of Citrulline Malate produced high NO boost and associated muscle pump.

Main reason for this is breakdown of Arginine post consumption. Enzyme Arginase in Intestine and liver breaks down Arginine. It has seen that less than 1% of orally consumed Arginine is available for NO boost. Citrulline however bypasses the liver and is not broken down by enzyme Arginase. Research has been shown that 80% of L-Citrulline is converted to Arginine and caused high NO boost.

Arginine-Or-Citrulline
Arginine-Or-Citrulline-image

Which Form of Citrulline is Better?

Citrulline when combined with Malic acid form Citrulline malate form has highest results on NO boost, even better than L-Citrulline. Citrulline malate is able to better regenerate Phospho creatine (PCr) which donates Phosphate group to ADP to regenerate ATP (energy) for the muscles. Thus, Citrulline malate provides muscle pump along with providing sustained endurance to carry out more reps without fatigue.

Arginine - Citrulline Pathway

Citrulline gets converted to Arginine in the kidneys which then get converted back to citrulline, byproduct being Nitric oxide with the help of Nitric oxide synthase enzyme causing vasodilation.

What works best in causing a Nitric oxide boost - L-Arginine, Citrulline Malate or Food Nitrates?

L-Arginine Citrulline Malate Food Nitrates
Dosage Less than 1% is left after breakdown by liver enzymes to produce any substantial effect. 6 gm/day is the ideal dosage researched to provide best nitric oxide boost. Beetroot juice has shown to have maximum effect on vasodilation (0.033 mmol/kg/day) 45 mins before activity had shown to have best result.
Maximum effect time 80 minutes 2-2.5 Hours No data found
Best time to take 1 Hours pre or post workout 20-45 minutes pre-workout 30-45 minutes pre-workout
Contraindications Contraindiacted in patients with low blood pressure, herpes, recent heart attack or kidney disorders Contraindiacted in patients with low blood pressure, herpes, recent heart attack or kidney disorders No such contraindication found

We Say

It is very obvious that Citrulline supplements are preferred over Arginine supplements, the reason being that Arginine is metabolized in the system. However, which form of citrulline works best? Both forms – L Citrulline and Citrulline Malate have their own pros and cons. Yet Citrulline Malate is the clear Winner. Advantage of using citrulline malate is that you don't have to load with it, whereas L-citrulline is most effective after a week of steady usage. It means you can take it right before your workout but still can experience immediate performance benefits. Whether you choose L-citrulline or citrulline malate, make sure to take the correct dosage. For L-citrulline, you required to take 2.4-6.0 gm/day for minimum seven days whereas, citrulline malate- 6 to 8 gm/day has been shown to yield benefits about an hour before exercise without using a loading phase. Your best bet for boosting muscle pump with ramified veins is to get a full 6-8-gram dose of citrulline malate. That way, combination of both L-citrulline +Citrulline malate will be best for greater vascularity.