From TMZ:
The family's statement also reveals John "quietly struggled with hypertensions. More than 40% of African-American men and women have high blood pressure, which also develops earlier in life and is usually more severe."
John's family encouraged his fans to recognize symptoms and visit heart.org for more information.
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Symptoms:
People may experience:
Muscular: difficulty walking, instability, paralysis with weak muscles, problems with coordination, stiff muscles, overactive reflexes, or paralysis of one side of the body
Visual: blurred vision, double vision, sudden visual loss, or temporary loss of vision in one eye
Whole body: fatigue, lightheadedness, or vertigo
Speech: difficulty speaking, slurred speech, or speech loss
Sensory: pins and needles or reduced sensation of touch
Facial: muscle weakness or numbness
Limbs: numbness or weakness
Also common: difficulty swallowing, headache, inability to understand, mental confusion, or rapid involuntary eye movement