Variation of Testosterone Levels in a Day - An Overview

Introduction

Testosterone is not only responsible for sexual development and function in men, but its level and effectiveness can have an influence on various aspects of men’s health, like the ability to achieve erections and enjoy sex, strengthen the bones, and even have an impact on the functioning of the brain. The levels of testosterone can vary with age as well as during the day. Plasma testosterone levels show a circadian variation. The levels reach a maximum when one sleeps and is low in the late afternoon.

Is All Testosterone Used by the Body?

The levels of testosterone are measured through blood tests. The normal range of testosterone falls between 300 to 1000 ng/dL. About 40 percent of men over 45 years of age have testosterone levels that fall below this range. However, a low value is not a cause for concern because the values are influenced by the time of the day that the healthcare professionals test one’s blood. The ideal time for testing one’s testosterone levels is between 7 to 10 a.m.

However, most testosterone in the blood is not actually utilized for use by the body. About 40 to 50 percent of testosterone is weakly adhered to a type of protein called albumin, and about 50 to 60 percent is tightly adhered to a protein manufactured by the liver called the sex hormone binding globulin (SHBG). Only one to three percent circulates as free testosterone.

Do Male Hormonal Levels Decline With Age?

Yes, the total testosterone levels fall with age at a level of about one percent each year after 30 years of age. Hence, a normal testosterone level may not be the same for a 70 and a 40-year-old man. Also, the levels of testostay be affected by an infection, tumor, or injury to the testicles. The pituitary gland in the body regulates the amount of hormones released by the body. Other factors that could affect the levels of testosterone include:

• Elevated blood pressure.

• Diabetes.

• High cholesterol.

• Overweight and obesity.

• Long-term use of certain medications like opioids.

• AIDS (Acquired Immunodeficiency Syndrome) and HIV (human immunodeficiency virus).

What Are the Symptoms Caused by Low Levels of Testosterone?

The following are the symptoms:

• Low sexual desire or drive.

• Low bone density.

• Low frequency and quality of erections.

• Low energy.

• Fatigue.

• Symptoms of depression.

• Reduced muscle mass and strength.

Is There a Daily Variation in Testosterone Levels?

Yes, the levels of testosterone vary each day as follows:

• The levels rise to a peak at about 8 a.m. and gradually decline throughout the day since the hormone is utilized to cater to the needs of the body’s other critical functions.

• The levels of testosterone hit the lowest at around 8 p.m., and the levels are restored overnight when one sleeps. It is for this reason that it is suggested that proper sleep is essential for good hormonal functioning, and poor sleep can result in low levels of testosterone.

• A study conducted in young men between the ages of 30 and 40 showed that these men had high levels of testosterone (both free and total) at around 8 a.m., and the levels were 30 to 35 percent higher than the levels measured in the mid-to-late afternoon. However, the difference dropped with age to approximately 10 percent at around 70 years of age.

• Since the numerical values of free testosterone and the amount of testosterone available for use by the body tend to change daily, reliable free testosterone tests should be done in the morning so that the amount of usable testosterone manufactured by the body can be precisely measured.

Do Testosterone Levels Vary Day to Day?

It is possible for this variation to occur. Scientists have found that testosterone levels can vary each day throughout the month in addition to the normal daily variation. However, there is no sufficient evidence to prove this. Also, determining how much the levels will peak and fall is impossible because every man’s body acts differently. In some men, the levels of testosterone may vary severely and may drop to low levels, which may result in the symptoms of low testosterone, while other men with better health may not experience variations that are serious enough to cause any obvious issues.

Do Testosterone Levels Vary With Seasons?

A few experts believe that it is likely possible for testosterone levels to vary with seasons. Recent research shows that testosterone levels may vary with seasons; however, more research is required.

• In a study conducted on 8400 police officers who were in their 40s and 50s, each participant was tested for serum total testosterone each morning at around 8 a.m. (the time when the level of testosterone was at its maximum).

• The study was conducted over a period of two years to enable researchers to gather sufficient data to analyze correlations between the levels of testosterone and the months in which they were measured.

• It was found that the mean total testosterone was lower in summer and spring, and the readings hit a peak during winter and fall. To be specific, the lowest mean level was in May (about 440 mg/dL), and the maximum was in January (600 mg/dL).

• Also, the seasonal variation of testosterone levels was influenced by the duration of sunlight and mean outdoor temperature. Shorter, cooler days resulted in high testosterone production.

How to Measure Testosterone Levels?

Testosterone levels can be measured through a finger-prick capillary blood sample or through saliva at home by the individual. However, the accurate and reliable method is through a blood sample taken from the vein. One should be fasting when the sample is taken so that the measured male hormonal levels are accurate. This is because the body’s production of testosterone may be influenced by the glucose levels, which usually drop after a meal. So, the ideal time to obtain the sample is early in the morning when one has not eaten or drunk anything.

Also, another benefit of procuring the sample early in the morning is that the testosterone levels in men keep fluctuating daily and tend to be higher in the morning than the rest of the day.

What Can Cause Low Testosterone Levels Apart From Diurnal Variations?

There can be several possible reasons for low testosterone levels. The most common causes include:

• Primary Hypogonadism (Testicular Disorder): Primary hypogonadism arises when there is something abnormal with the testicles that prevents them from manufacturing normal levels of testosterone. It is also called hypergonadotropic hypogonadism.

• Secondary Hypogonadism (Dysfunction of the Pituitary Gland or Hypothalamus): Secondary hypogonadism is also known as hypogonadotropic hypogonadism. In this condition, there are low levels of follicle-stimulating hormone (FSH) and luteinizing hormone (LH). These low levels can result in decreased sperm production and testosterone levels.

Is It Possible to Prevent Low Testosterone Levels?

It is not known how to prevent low testosterone levels due to damage to the testicles, pituitary gland, or hypothalamus or as a result of genetic conditions. However, a few lifestyle changes that may help keep testosterone levels within the normal range include:

• Exercise.

• Consumption of a healthy diet.

• Refraining from excessive use of drugs and alcohol.

• Weight management.

Conclusion

Normal variations in testosterone levels and long-term and clinically low testosterone levels are different issues. Testosterone levels can fluctuate within a day, daily, or in various seasons. One must have knowledge about this variation to distinguish it from low testosterone levels. The levels of testosterone are at their peak early in the morning and gradually fall during the rest of the day. So, testing testosterone levels early in the morning is the ideal method of determining testosterone levels accurately.