Winter is the peak season for heart attacks. A recent study has found that this season accounts for one-third more deaths than in the summer and early fall.

The higher numbers are due to a combination of factors. For one thing, the abundance of food, alcohol, salt and stress during the holidays may make you more susceptible at this time of year. There is also the exposure to particles emitted from burning fireplace wood, which irritate the lungs, decrease oxygen in the bloodstream and place stress on the heart.

The winter surge in heart attacks holds true for warm as well as cold climates, but there is a stronger association between cooler temperatures and deaths from heart disease. During the colder months, the workload on the heart is increased. Overexertion is common -- shoveling snow, for example -- which has been shown to increase the occurrence heart attacks.

It is important to recognize the earliest signs of a heart attack. Sometimes they occur intermittently and give the false impression that they will go away. However, don’t ignore the following early warning symptoms that are seen in 50 percent of heart attack victims:

• An ache, pressure, tightness, squeezing, or burning sensation or a feeling of fullness in the center of the chest.
• Discomfort that comes on with activity and is relieved by rest.
• Pain persisting for hours or days before a heart attack.
• Pain that increases in frequency and intensity over time.

Late symptoms are:

• Chest pain above the navel.
• Pain in the arm, chest, throat, jaw and back.
• Numbness, weakness.
• Shortness of breath, pallor.
• Nausea and vomiting.
• Profuse sweating.