The pH level of blood is just one of the many important factors that must be in the right place for a happy, healthy body to operate.

In humans, an arterial blood pH level anywhere between 7.35 and 7.45 is considered normal.

That number is just slightly above neutral on the pH, or potential hydrogen, scale. The scale goes from 0 to 14 and measures whether a solution is acid or alkaline. Neutral is 7, which indicates that a substance is an equal mix of acids and bases. A substance with a pH value from 0 to 7 is acidic; anything with a score above 7 to 14 is considered a base. So, with blood, a pH higher than 7.45 the blood’s acidity is too low, and below 7.35 means the blood’s acid level is too high.

Healthy kidneys and lungs work hard to help our bodies maintain a balance of 7.4, but there are a number of reasons that blood pH levels can rise and fall. When they do, it’s called either acidosis or alkalosis.

Acidosis occurs when blood pH levels dip below 7.35. There are two types of acidosis: metabolic and respiratory. During metabolic acidosis, your body either isn’t producing enough acid, or it can’t get rid of enough acid. During respiratory acidosis, your body lacks the bases to balance out the amount of acid in your system.

Metabolic acidosis stems from problems with the kidneys. Several kidney issues can lead to metabolic acidosis, including poorly controlled diabetes, extreme diarrhea or vomiting, and kidney failure. A buildup of lactic acid as a result of issues including heart failure, cancer, chronic alcohol use, seizures, liver failure or low blood sugar can also lead to metabolic acidosis.

Respiratory acidosis occurs when there is too much carbon dioxide (CO2) in the body. This can happen for a number of reasons, including chronic breathing conditions like asthma, a chest injury or nervous system problems.

Doctors have to attack the root of the problem to control acidosis entirely. For example, someone with metabolic acidosis might need a kidney transplant. Many acidosis patients at some point receive an IV filled with a sodium bicarbonate or baking soda solution. This helps to raise the pH of the blood immediately.

When blood pH levels rise above 7.45, alkalosis occurs. There are five different types of alkalosis, and they occur when your body either isn’t getting enough CO2 or has too much bicarbonate. Respiratory alkalosis is one of the more common types for otherwise healthy people because CO2 levels in the lungs can fall at high altitudes or in the case of severe fever, hyperventilation from anxiety or aspirin poisoning. Other types of alkalosis are usually related to existing health problems such as kidney disease or prolonged vomiting. Treatment depends on the underlying cause, but some respiratory alkalosis patients can recover after taking slow, deep breaths. Others suffering from alkalosis can see pH levels return to normal after ingesting fluids with plenty of electrolytes, chloride or potassium.

Since a healthy blood pH level depends on a working set of lungs and kidneys, maintaining that balance can at times feel beyond your control. Paying attention to your overall wellness by staying active, eating a healthy diet and not overusing drugs or alcohol can go a long way toward keeping your blood pH where it needs to be.