Healthy Blood Flow, Blood Pressure, and Nitric Oxide
- Benjamin Payson
- 3 hours ago
- 4 min read
If you care about endurance, recovery, heat performance, or long-term cardiovascular health, blood flow is everything.
Oxygen delivery. Nutrient transport. Thermoregulation. Electrolyte balance. All of it depends on one key molecule:
Nitric oxide (NO).
Let’s break down:
What nitric oxide actually does
Where it works in the body
How it affects blood pressure and performance
Signs your body may not be producing enough
And how to support healthy NO levels naturally
What Is Nitric Oxide (NO)?
Nitric oxide is a signaling molecule produced inside your blood vessels by the endothelium (the inner lining of your arteries)¹.
Its primary job:
Tell blood vessels to relax and widen.
This process is called vasodilation¹.
When nitric oxide levels are adequate:
Blood vessels dilate
Blood pressure stays regulated¹
Oxygen delivery improves
Muscles perform better
Heat dissipates more effectively
When nitric oxide production declines:
Blood vessels stiffen
Blood pressure rises²
Circulation becomes less efficient
Exercise feels harder than it should
Where Nitric Oxide Is Used in the Body
Nitric oxide is produced and used in multiple systems:
1. Cardiovascular System
Produced by endothelial nitric oxide synthase (eNOS), nitric oxide regulates vascular tone, blood pressure, and blood flow distribution¹.
2. Skeletal Muscle
NO increases blood flow to active muscle tissue and improves mitochondrial efficiency during exercise³.
3. Brain
Neuronal nitric oxide acts as a neurotransmitter and plays a role in memory and neurovascular coupling⁴.
4. Immune System
Inducible nitric oxide synthase (iNOS) produces NO as part of the immune defense against pathogens⁵.
5. Thermoregulation
NO-mediated vasodilation increases skin blood flow, allowing the body to dissipate heat during exercise and environmental stress⁶.
Nitric Oxide and Blood Pressure
Blood pressure is largely determined by:
Nitric oxide directly reduces vascular resistance by relaxing smooth muscle in arterial walls¹.
When arteries relax and widen:
Resistance drops
Blood pressure decreases²
Blood flows more efficiently
Reduced NO bioavailability is strongly associated with:
Hypertension²
Arterial stiffness²
Endothelial dysfunction²
Endothelial dysfunction is one of the earliest detectable changes in cardiovascular disease².
Why Nitric Oxide Matters Even More in the Heat
When you exercise in high temperatures:
Skin blood flow must increase to cool you
Muscles demand more oxygen
Sweat rate increases
Plasma volume decreases
Nitric oxide becomes critical for:
Efficient heat dissipation⁶
Maintaining stroke volume
Reducing cardiac strain
Preventing performance drop-off
Impaired vasodilation increases cardiovascular strain during heat stress⁶.
The Age Factor
Nitric oxide production declines with age due to:
Reduced eNOS activity
Increased oxidative stress
Reduced nitrate conversion efficiency²
Endothelial function measurably declines beginning in early adulthood and continues progressively with aging².
Signs You May Have Low Nitric Oxide Levels
While nitric oxide itself isn’t directly “felt,” patterns associated with endothelial dysfunction include:
1. Elevated Resting Blood Pressure²
2. Cold Hands and Feet (poor peripheral vasodilation)
3. Reduced Exercise Endurance³
4. Slower Recovery Between Intervals
5. Increased Cardiovascular Strain in Heat⁶
These signs are not diagnostic, but they can indicate impaired vascular function.
How the Body Produces Nitric Oxide
There are two primary pathways:
1. The L-Citrulline → L-Arginine → NO Pathway
Nitric oxide synthase enzymes convert L-arginine into nitric oxide¹.
2. The Nitrate → Nitrite → Nitric Oxide Pathway
Dietary nitrates are converted by oral bacteria into nitrite, then into nitric oxide — especially during hypoxia or exercise⁷.
This secondary pathway becomes increasingly important:
During exercise
In low-oxygen conditions
With aging
In heat stress
Evidence for Dietary Nitrates and Blood Pressure
Dietary nitrate supplementation (such as beetroot juice) has been shown to:
Reduce systolic blood pressure⁸
Improve endothelial function⁸
Improve exercise efficiency³
Reductions in systolic blood pressure of ~4–10 mmHg have been observed in controlled trials⁸.
That magnitude is clinically meaningful.
Hydration + Nitric Oxide = Circulatory Efficiency
Hydration status directly affects blood viscosity and plasma volume.
If plasma volume drops:
Vascular resistance rises
Cardiac workload increases
Heat strain escalates
Nitric oxide works best when blood volume is maintained. Hydration supports circulation. Circulation supports thermoregulation. Thermoregulation protects performance.
Final Takeaway
Nitric oxide is central to:
Blood pressure regulation¹²
Exercise performance³
Heat tolerance⁶
Endothelial health²
If you’re noticing:
Rising blood pressure
Cold extremities
Reduced endurance
Higher cardiovascular strain in heat
It may be worth evaluating your vascular health and nitric oxide support, alongside proper hydration and electrolyte balance.
Healthy circulation isn’t just about longevity.
It’s about performance, especially when conditions get hot.
Sources
Robert F. Furchgott, Louis J. Ignarro, & Ferid Murad. Nobel Prize in Physiology or Medicine (1998) — Discovery of nitric oxide as a signaling molecule in the cardiovascular system.
John A. Vita. Endothelial function and cardiovascular disease. Circulation.
Andrew M. Jones et al. Dietary nitrate supplementation reduces oxygen cost of exercise. Journal of Applied Physiology.
Solomon H. Snyder. Nitric oxide as a neuronal messenger. Science.
Salvador Moncada. Nitric oxide biology and immune defense. Pharmacological Reviews.
Christopher G. Minson. Nitric oxide and thermoregulatory skin blood flow. Journal of Applied Physiology.
Norman Hord et al. Dietary nitrates and the nitrate-nitrite-NO pathway. American Journal of Clinical Nutrition.
Amrita Ahluwalia et al. Dietary nitrate lowers blood pressure. Hypertension.
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