As we age, our bodies undergo numerous physiological changes that can make us more susceptible to cold, leading to shivering. While shivering is a natural response to a drop in body temperature, in older adults, it can be triggered more easily and may signal other health issues. Understanding these factors is key to providing proper care and knowing when to seek medical advice.
The Physiology of Aging and Thermoregulation
The human body's ability to control its internal temperature, a process called thermoregulation, becomes less efficient over time. Several key changes contribute to this decline:
- Slower Metabolism: The body's metabolic rate, which is the speed at which it converts food into energy and heat, naturally decreases with age. This means older adults generate less internal heat to keep themselves warm, making them more vulnerable to the cold.
- Loss of Subcutaneous Fat: The layer of insulating fat just beneath the skin, which helps conserve body heat, thins over the years. With less insulation, the body loses heat more rapidly, triggering the shivering reflex even in mildly cool environments.
- Decreased Circulation: As blood vessels lose elasticity, circulation can become less efficient. Poor blood flow, especially to the extremities like hands and feet, can cause them to feel cold and trigger a shivering response throughout the body.
- Impaired Nervous System Response: The hypothalamus, the part of the brain that controls body temperature, can be affected by aging and conditions like dementia. This can lead to a diminished ability to detect temperature changes or a less effective shivering response, putting an individual at greater risk.
Medical Conditions and Shivering
Beyond normal age-related changes, several medical conditions can cause or worsen shivering in older adults. Some are systemic issues that affect the entire body, while others are neurological.
- Hypothermia: This is a dangerous medical emergency that occurs when the body loses heat faster than it can produce it, causing a dangerously low core temperature. For the elderly, hypothermia can occur indoors even at moderate temperatures (e.g., in the mid-70s) due to their reduced ability to generate heat. It can cause confusion and disorientation, making it difficult for the person to recognize they are in danger.
- Infections: A sudden onset of unexplained shivering can be a sign that the body is fighting an infection, such as pneumonia or a urinary tract infection (UTI). This is often accompanied by a fever, but not always. The shivering response helps generate heat to kill bacteria or viruses.
- Anemia: A low red blood cell count (anemia) can lead to feelings of cold and shivering. Red blood cells are responsible for carrying oxygen throughout the body, and a lack of them can affect heat production and delivery to tissues.
- Hypoglycemia: Low blood sugar, particularly in people with diabetes, can cause a person to feel shaky, cold, and weak. This occurs when the body's energy levels drop, affecting its ability to function correctly.
- Thyroid Problems: An underactive thyroid gland (hypothyroidism) can cause a person's metabolism to slow down, leading to increased cold sensitivity and shivering.
Tremors vs. Shivers
It's important to distinguish between shivering, which is often a thermoregulatory response, and tremors, which are involuntary, rhythmic muscle contractions. While both involve shaking, they have different origins and implications. In older adults, true shivering from cold may be less common than tremors caused by neurological conditions.
| Feature | Shivers (Thermoregulatory) | Tremors (Neurological) |
|---|---|---|
| Cause | Response to cold temperatures, fever, or low body temperature. | Disruption in the parts of the brain that control movement (cerebellum). |
| Appearance | Generalized shaking; often rapid, short-lived, and full-body. | Rhythmic, involuntary shaking, often localized to hands, head, or arms. |
| Trigger | Exposure to cold, fever, or a significant drop in core body temperature. | Action (reaching for something), rest (hands in lap), or specific tasks. |
| Effect of Distraction | Less likely to be influenced by mental focus or distraction. | Can sometimes decrease or disappear when the person is distracted. |
| Associated Symptoms | Can include chattering teeth, goosebumps, and feeling cold. | Can be accompanied by other neurological symptoms, such as balance issues or speech changes. |
| Commonality | Less frequent in older adults unless exposed to cold. | Relatively common; essential tremor affects up to 10% of people over 65. |
Medications and Other Factors
Certain medications and lifestyle factors can also play a role in why old people get shivers or tremors. Polypharmacy, the use of multiple drugs for various conditions, increases the risk of side effects.
- Medication Side Effects: Drugs commonly prescribed to older adults can cause shivering or tremors as a side effect. These include certain antidepressants, asthma medications, heart medications, and steroids. The risk increases with age due to slower drug metabolism.
- Anxiety and Stress: Strong emotions can trigger a 'fight or flight' response, causing a surge of adrenaline that can manifest as shaking or shivering. Stress, anxiety, and fatigue are known to exacerbate both essential tremor and general shakiness.
- Sleep Deprivation: Not getting enough sleep can affect the hypothalamus, the part of the brain that regulates body temperature. Fatigue can also slow metabolism, leading to a reduced ability to stay warm.
Conclusion: Seeking Help for Shivers and Tremors
While some cold sensitivity is a normal part of aging, persistent shivering, unexplained shaking, or signs of hypothermia should not be ignored. It is essential for older adults and their caregivers to be vigilant and aware of the potential causes. For caregivers, monitoring indoor temperatures, encouraging warm, layered clothing, and ensuring a healthy diet can help mitigate the risk of cold-induced shivering. For unexplained tremors or shivering, especially if it interferes with daily activities or is accompanied by other symptoms like confusion, a medical evaluation is critical to rule out or treat any underlying conditions. Regular check-ups can also help manage potential medication side effects and other risk factors.
Prevention and Management Tips
- Regulate Home Temperature: Set thermostats to at least 68°F and check for drafts.
- Dress in Layers: Wearing loose, layered clothing helps trap body heat. Encourage seniors to wear hats, scarves, and warm socks.
- Eat Warm Meals and Drink Warm Fluids: Hot beverages and hearty meals can help raise core body temperature.
- Stay Active: Gentle exercise, even walking in place, can improve circulation and generate heat.
- Medication Review: Consult with a doctor or pharmacist to review all current medications for potential side effects.
Note: If you suspect hypothermia (body temperature below 95°F), seek immediate medical attention. The symptoms, such as confusion and slurred speech, may be subtle in older adults.
