TENS Units vs Pain Creams vs Ice Packs: What Actually Helps Chronic Pain?
- Dr. Jason Winkelmann
- 5 hours ago
- 7 min read
TL;DR
Yes, devices like TENS units, neuromuscular stimulators, analgesic creams, and hot or cold packs can reduce pain temporarily. They work by influencing how pain signals travel through the nervous system, primarily through a mechanism called the gate control theory of pain. However, these tools do not fix the underlying causes of chronic pain. They modify how pain signals are processed for a short period of time, which is why relief often disappears when the treatment stops. Understanding why these therapies work helps patients use them more intelligently while recognizing their limitations.
What Patients Are Usually Told
If you live with chronic pain, you've likely encountered an overwhelming number of pain-relief products:
TENS units
Neuromuscular electrical stimulation devices
Menthol or capsaicin pain creams
Heating pads
Ice packs
Many advertisements promise pain relief by targeting the source of pain.
That explanation sounds reasonable. If something hurts, the assumption is that the problem must be located in the tissues where you feel the pain.
But this is where the explanation becomes incomplete.
Pain does not simply come from tissues like muscles or joints. Pain is a signal generated by the nervous system, and that signal is constantly being modified before it ever reaches your brain.
This is where the gate control theory of pain becomes important.
Symptoms Are Signals, Not the Problem
Pain is not the underlying problem. Pain is information.
Your nervous system constantly monitors the body for potential threats. When it detects something concerning, it generates a signal that travels from peripheral nerves to the spinal cord and eventually to the brain.
Your brain then interprets that signal as pain.
But what many patients are never told is that the nervous system has multiple layers of filtering systems that determine how much of that signal actually reaches the brain. In other words, pain is not simply a direct message from the body. It is a message that gets edited along the way.
The Physiology Most Patients Are Never Taught
To understand why many pain-relief tools work, we first have to understand how nerve signals travel.
Three Types of Sensory Nerve Fibers
Your body uses different types of nerve fibers to transmit sensory information.
A-Beta Fibers
These fibers respond to:
touch
pressure
vibration
joint movement
They are large and heavily insulated with myelin, which allows them to transmit signals very quickly.
A-Delta Fibers
These fibers transmit:
sharp
localized
immediate pain
They have moderate myelin insulation, so their signals travel slightly slower.
C Fibers
These fibers transmit:
dull
aching
burning
throbbing pain
They are very small and lack myelin, which makes them the slowest. This is important because most chronic pain symptoms are transmitted through C fibers.
The Gate Control Theory of Pain
The spinal cord acts like a gatekeeper for incoming nerve signals.
Imagine a security checkpoint between your body and your brain. Every signal must pass through this checkpoint before reaching your brain.
Inside the spinal cord are specialized cells called inhibitory interneurons. Their job is to block or reduce pain signals before they travel upward.
This process is known as descending inhibition.
When these inhibitory systems are active, fewer pain signals reach the brain. When they are inactive, more signals get through.
This mechanism explains why different injuries can feel dramatically different even though nerves technically fire at full intensity every time they are stimulated.
Why Some Injuries Hurt More Than Others
Consider two common experiences:
stubbing your toe
bumping your elbow
Both involve nerve signals traveling toward the brain. But your nervous system evaluates the situation and predicts how dangerous it is.
If the brain interprets the situation as minor, it activates descending inhibition, allowing only a small amount of signal through.
If the brain interprets the situation as more threatening, it reduces inhibition and allows more signal to pass.
This filtering process is the basis of the gate control theory of pain.
What Changes in Chronic Pain
In chronic pain conditions, this filtering system often stops working correctly. The nervous system becomes more sensitive to incoming signals, a process known as central sensitization.
Instead of blocking unnecessary signals, the spinal cord begins allowing too many signals to reach the brain.
This is why people with chronic pain often experience:
pain from minor movement
sensitivity to touch
In simpler terms, the nervous system’s gate becomes too easy to open. This is a major reason why treatments that focus only on tissues often fail to fully resolve chronic pain.
How TENS Units Reduce Pain
A TENS unit stands for Transcutaneous Electrical Nerve Stimulation. These devices send small electrical pulses through the skin to stimulate nerves. The goal is to activate A-beta fibers, the fast sensory fibers responsible for vibration and touch.
When these fibers fire rapidly, they activate inhibitory interneurons in the spinal cord. This increases descending inhibition, which reduces the amount of pain signal that reaches the brain.
In simpler terms, TENS units work by flooding the spinal cord with competing sensory signals, which partially closes the pain gate.
This is why many people feel relief while the device is running.
However, once the stimulation stops, the nervous system typically returns to its previous state. This is why TENS units often provide temporary relief rather than long-term resolution.
Neuromuscular Electrical Stimulation Devices
Neuromuscular electrical stimulators, such as the NeuroMD work slightly differently. Instead of targeting sensory nerves, these devices stimulate motor neurons, which cause muscles to contract.
This can serve several purposes:
muscle re-education after injury
preventing muscle atrophy
restoring normal movement patterns
Because these devices still stimulate sensory nerves indirectly, some pain-relief effects may occur through the same gate control mechanisms.
However, their primary role is improving muscle function, not directly treating chronic pain. For patients with true muscle dysfunction, such as after surgery or neurological injury, these devices can be extremely useful.
But in many chronic pain conditions, muscle weakness is not the primary driver of symptoms.
Why Analgesic Creams Work
Topical pain creams work through two main mechanisms depending on their active ingredient.
Capsaicin Creams
Capsaicin is the compound responsible for the heat in chili peppers. It works by disrupting the action potential cycle of pain fibers.
Normally, a nerve must:
fire
reset
fire again
Capsaicin interferes with this reset process, temporarily preventing the nerve from firing again.
This can reduce pain signals, but only while the chemical effect is present. Once the compound wears off, the nerve resumes normal signaling.
Menthol and Camphor Creams
Cooling creams like menthol and camphor work differently. They stimulate A-beta sensory fibers, which activate the same inhibitory systems involved in the gate control theory.
This produces a cooling sensation while simultaneously reducing the amount of pain signal reaching the brain. Again, the relief lasts only as long as the stimulation continues.
How Cold Packs Reduce Pain
Cold therapy works through two primary mechanisms.
Reduced Blood Flow
Cold causes vasoconstriction, which reduces blood flow to the area. This can temporarily reduce swelling and inflammation.
Sensory Nerve Stimulation
Cold also stimulates A-beta sensory fibers, activating the same gate-control inhibition discussed earlier. Together, these effects can significantly reduce pain in the short term.
However, excessive cold can impair healing if it suppresses inflammation too much. Inflammation, while uncomfortable, is part of the body's normal repair process.
Why Heat Feels Good
Heat works through almost the opposite mechanism.
Heat causes vasodilation, increasing blood flow to tissues.
This brings:
oxygen
nutrients
metabolic support
Heat also relaxes muscle tissue, which can reduce protective muscle guarding.
But like cold therapy, excessive use can create problems. Leaving a heating pad on for long periods may actually promote excess inflammation and slow recovery.
A Clinical Insight From Practice
Patients frequently bring these devices into the clinic and ask whether they should continue using them.
The honest answer is usually yes, but with realistic expectations.
If a therapy temporarily reduces symptoms, it can be a useful tool. It may help:
calm down painful flare-ups
allow gentle movement or exercise
make daily activities more tolerable
But if relief disappears as soon as the treatment stops, it tells us something important.
It tells us that the therapy is modifying the pain signal, not correcting the deeper processes that are generating it.
Understanding this distinction prevents frustration and helps patients choose treatments more strategically.
Why These Tools Don’t Fix Chronic Pain
The problem with symptom-focused treatments is not that they are ineffective. The problem is that they operate at the level of the pain signal itself.
Chronic pain usually emerges from interactions between multiple physiological systems: physically, biochemically, and emotionally.
Unless these systems are addressed, the nervous system often remains sensitized. This is why many chronic pain sufferers cycle through treatments that temporarily help but never fully resolve the condition.
Education Is the Most Powerful Tool
One of the most powerful tools for managing chronic pain is understanding how the body actually works. When patients understand the mechanisms behind treatments, two things happen.
They are more likely to use therapies appropriately.
They can recognize when a treatment is helping manage symptoms versus addressing the deeper causes of pain.
This distinction is essential.
Because when you understand the physiology of pain, you move one step closer to treating the systems that generate it, not just the symptoms it produces.
Reframing Pain Relief
Devices, creams, and temperature therapies can all provide meaningful relief. But relief is not the same thing as resolution.
Understanding the gate control theory of pain reveals why these tools work, and why they eventually reach their limits.
When patients learn how pain signals are generated and regulated by the nervous system, the conversation changes. Instead of endlessly chasing symptom relief, treatment can shift toward restoring balance to the systems that created the pain in the first place.
And that shift is often where meaningful recovery begins.
Written By:
Dr. Jason Winkelmann
Naturopathic doctor, Chiropractor, Chronic Pain Specialist, and Educator
Frequently Asked Questions
Are TENS units safe to use daily?
Yes, most people can safely use TENS units regularly. However, they should be viewed as temporary symptom-relief tools, not long-term solutions for chronic pain.
Do pain creams heal injured tissues?
No. Pain creams modify nerve signaling but do not repair damaged tissues or address chronic pain mechanisms.
Should I use heat or ice for chronic pain?
Both can help. Ice tends to reduce inflammation and numb pain, while heat improves circulation and relaxes muscles. Alternating them can sometimes provide the best results.
Why do these treatments stop working after a while?
Because they influence how pain signals are processed, not the underlying systems producing those signals.
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