Feeling tired after a long day is normal.

The concern is persistent fatigue that doesn't improve with adequate sleep and rest.

Ongoing fatigue can have countless causes, including:

• Poor sleep
• Stress
• Anemia
• Thyroid disorders
• Infections
• Nutritional deficiencies
• Depression
• Medication effects
• Chronic medical conditions

Fatigue alone rarely points to one specific diagnosis.

But if your energy level has changed significantly for no obvious reason—and the problem continues for weeks—it is worth discussing with a healthcare professional.

7. Unexplained Weight Changes

A few pounds of fluctuation can happen naturally.

Changes in hydration, diet, exercise, hormones, and bowel habits can all affect body weight.

The concern is significant, unintentional weight loss or gain without an obvious explanation.

Unexpected weight loss can occur with gastrointestinal disorders, thyroid disease, diabetes, infections, mental-health conditions, and many other illnesses.

Unexpected weight gain can also have multiple causes, including fluid retention, hormonal changes, medication effects, and changes in calorie intake or activity.

Don't diagnose yourself based on the scale alone.

Look at the broader pattern and seek medical advice when the change is persistent or substantial.

8. Changes in Urine

Your urine naturally changes depending on how much fluid you drink and what you've eaten.

Dark yellow urine after not drinking enough water is usually simply a sign that you need more fluids.

But persistent changes can sometimes deserve attention.

Examples include:

Blood in the urine

Persistent unusually dark urine

Cloudy urine accompanied by other symptoms

A major change in urination frequency

Pain or burning when urinating

Blood in the urine should not simply be ignored, even if it happens only once.

Urinary infections, kidney stones, medications, dehydration, and several other conditions can produce changes in urine.

A healthcare professional can determine the underlying cause.

9. Persistent Changes in Bowel Habits

Your bowel habits naturally vary from person to person.

Diet, stress, travel, medications, and changes in fiber intake can all affect digestion.

But a persistent change from your normal pattern may warrant attention.

Examples include:

• Ongoing constipation
• Persistent diarrhea
• Repeated unexplained abdominal discomfort
• Blood in the stool
• Black or tar-like stools
• A persistent feeling that you haven't completely emptied your bowel

These symptoms have many possible causes, and most are not cancer.

Nevertheless, blood in the stool or a persistent unexplained change in bowel habits should be evaluated, particularly in older adults or people with relevant family or personal medical history.

10. Persistent Swelling

Swelling can occur after an injury, prolonged sitting, salty meals, or hormonal changes.

But persistent swelling—especially when it is new—can sometimes reflect an underlying problem.

Swelling in the legs may be associated with venous problems, medications, kidney disease, heart conditions, or other causes.

Sudden swelling of one leg, particularly when accompanied by pain, warmth, or redness, requires prompt medical attention because a blood clot is one possible cause.

If swelling is accompanied by sudden chest pain, severe shortness of breath, coughing up blood, or fainting, seek emergency medical care.

One Symptom Rarely Tells the Whole Story

This is one of the most important things to remember when reading health information online.

A rash does not automatically mean cancer.