Lower back spasms, also often referred to as cramps, occur because of inflammation that follows an injury to the muscles in your lower back. Besides being painful, lower back spasms can increase your blood pressure because as your muscles repeatedly contract, they restrict regular blood blow. Increases in blood pressure should be temporary, but people with already high blood pressure numbers should visit their doctor.
Muscle spasms are caused by a muscle being strained, which means it’s been overstretched or torn, according to Dr. Steven Ludwig at the University of Maryland Medical Center. Lifting an object that’s too heavy and twisting is a common cause of lower back muscular strain. Muscle spasms in the lower back can be debilitating. With rest, muscle strains will heal and the muscle spasms will cease in a couple of days or weeks.
According to the National Heart Lung and Blood Institute, blood pressure is the force that pushes against your artery walls as your heart pumps. Blood pressure is measured as systolic, which is the pressure when the heart beats, and diastolic, which is the pressure when your heart is at rest. Normal blood pressure is less than 120 systolic and less than 80 diastolic. When blood pressure is too high, it can cause damage, and over time it can lead to heart disease, stroke or kidney failure. High blood pressure is measured at 140 or above systolic and 90 or above diastolic. Blood pressure does not remain constant, but fluctuates as you begin and stop physical activity or are anxious or relaxed.
According to a study by J.L. Corbett published by the "Journal of Physiology," muscle spasms cause an increase in blood pressure. Because of the heavy blood flow to your lower back area, active muscle spasms can make a significant impact on your blood pressure. When your muscles spasm, they can reduce blood flow through your arteries, which, in turn, increases blood pressure. The changes begin within two to three seconds from the start of the spasms and your blood pressure reaches its maximum in 20 to 30 seconds. He concluded that the increase in blood pressure was due to a spinal sympathetic reflex that occurs following muscle contractions.
Prevention and Treatment
To decrease your risk of lower back spasms and a subsequent rise in blood pressure, consistently participate in physical activity. Dr. Ludwig states that people who are active and physically conditioned are less likely to suffer from lower back strains. If you have lower back spasms, MayoClinic.com recommends performing stretching exercises. Lie on your back and hug your knees against your chest. The increase in blood pressure from muscle spasms should be temporary and should subside once your spasms subside. However, if you already suffer from high blood pressure, you should visit a medical professional.