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Published on: Jul 09, 2020
2 minute read
By: Dr Rakesh Choudhary

COVID- 19 Tests – What Do You Need To Know?

COVID- 19 tests – What do you need to know?

Author: Dr. Rakesh Choudhary MBBS, MS, FRCS UK, FRCS Orth UK, MChOrth UK.

Dr. Choudhary is a practicing consultant surgeon in the UK.

So many of us think it is not their job to learn about COVID-19 tests and this should be left for the experts and governments to decide about these tests. But I strongly suggest the public must have a basic understanding of these tests which they may have to have themselves.

Basically there are two types of tests, one which can detect the virus in the body and the other one which tells if the person had the previous infection.

Virus test

The virus test detects an active infection. It detects the genetic material (RNA) of the virus during an active infection. It is also called a PCR (polymerase chain reaction) test or nucleic acid test and is sometimes inaccurately called an antigen test.

A swab is taken from deep in the back of your throat and deep in the nose. The swab should go deep up to 7-8 cm and is generally uncomfortable for the patient. Swabbing patients using the correct technique is paramount in ensuring an accurate result. By simply swabbing the inside of the nasal passage is not deep enough to verify that the virus is present.

What does virus testing tell you?

This test tells us if a patient is actively infected with the COVID-19 virus. Virus testing is used mainly for the diagnosis of COVID-19.

When should it be done?

The virus test works best during the first seven days of symptoms.

The coronavirus can be detected in swabs even before symptoms of illness first appear . This is why people can be infectious for a few days before the onset of symptoms, which usually appear about 5 days after the virus infects. Some people have no symptoms throughout their infection but are positive on the virus test and infectious to others. After a few days of illness, the concentration of the virus falls (as seen in swab samples) and the symptoms of the illness usually recede.

Accuracy of the test

In a person with COVID-19, the test is less likely to give a positive result late in the course of infection once the virus has been cleared by the immune system, or if an inadequate sample is taken from the nose or throat. There are concerns that the rate of ‘false negative’ test results could be as high as 30% and a significant number of people are wrongly being told they do not have the virus.

Antibody test

Antibody tests check your blood by looking for antibodies, which may tell you if you had a past infection with the virus that causes COVID-19. Antibodies are protein structures that are produced by the immune system in response to certain infections. The antibody can help fight off infections and can provide protection against getting that disease again (immunity). Antibodies are disease-specific. For example, measles antibodies will protect you from getting measles if you are exposed to it.

The antibody test detects the presence of antibodies as a marker of past infection. The antibody test (blood test) will only detect infections after the immune system has produced antibodies that recognize the virus. This happens approximately 7–10 days after symptoms develop.

Tests carried out a week after a patient develops symptoms will detect only 30% of people who had COVID-19 infection. Accuracy increases to 72% at two weeks and to 94% in the third week. Some people may take even longer to develop antibodies, and some people who are infected may not ever develop antibodies.

Interpretation of the antibody test is complex for non-medical people. Basically having antibodies to the virus that causes COVID-19 may provide protection from getting infected with the virus again. If it does, we do not know how much protection the antibodies may provide or how long this protection may last.

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Sleep Debt and Its Impact on the Body: Hidden Risks of Chronic Sleep Loss

Sleep is not a luxury; it is a biological necessity. Yet in today’s fast-paced world, many people consistently sacrifice sleep due to work demands, screen time and stress. Over time, insufficient sleep accumulates into what is known as sleep debt. Understanding sleep debt and its impact on the body is essential because chronic sleep loss silently affects nearly every organ system.

According to the World Health Organization and global sleep research, chronic sleep deprivation is associated with increased risk of cardiovascular disease, metabolic disorders and mental health conditions.

What Is Sleep Debt?

Sleep debt refers to the cumulative effect of not getting enough sleep.

For example:

if you need 8 hours but sleep 6 hours daily
you accumulate 2 hours of sleep debt per night

Over a week, that equals 14 hours of lost sleep.

This deficit places strain on the body.

Why Sleep Is Critical for Health

Sleep supports:

brain function
immune response
hormonal regulation
tissue repair
memory consolidation

Without adequate sleep, these processes become impaired.

Immediate Effects of Sleep Debt

Short-term consequences include:

daytime fatigue
poor concentration
mood swings
irritability
reduced reaction time

Even one night of poor sleep affects cognitive performance.

Sleep Debt and Hormonal Imbalance

Sleep regulates several key hormones.

Chronic sleep loss disrupts:

cortisol
insulin
leptin and ghrelin (hunger hormones)

This imbalance affects appetite, stress and metabolism.

Impact on Metabolic Health

Sleep debt increases:

insulin resistance
blood sugar fluctuations
abdominal fat accumulation

ICMR and NFHS-5 data show rising metabolic disorders in India, partly linked to lifestyle patterns including poor sleep.

Increased Risk of Obesity

When sleep is insufficient:

appetite hormones increase
cravings for high-calorie foods rise
impulse control weakens

Sleep deprivation promotes weight gain.

Sleep Debt and Immunity

The immune system relies heavily on sleep.

Chronic sleep loss:

reduces infection-fighting cells
increases inflammation
slows recovery from illness

Lancet research confirms that sleep deprivation weakens immune response.

Cardiovascular Consequences

Sleep debt increases risk of:

hypertension
heart disease
stroke

Poor sleep affects blood pressure regulation and vascular health.

Mental Health Impact

Sleep and mental health are deeply connected.

Sleep debt contributes to:

anxiety
depression
emotional instability

Chronic insomnia is both a cause and consequence of mental health disorders.

Cognitive Decline and Brain Health

Lack of sleep impairs:

memory
attention
decision-making

Over time, chronic sleep deprivation may increase risk of neurodegenerative disorders.

Sleep Debt and Inflammation

Chronic sleep loss elevates inflammatory markers.

Persistent inflammation contributes to:

metabolic syndrome
cardiovascular disease
autoimmune conditions

Preventing sleep debt reduces systemic inflammation.

Can Sleep Debt Be Recovered?

Short-term sleep debt can be partially recovered through:

consistent longer sleep
improved sleep hygiene

However, chronic sleep deprivation requires long-term behavioural changes.

Weekend “catch-up sleep” offers temporary relief but does not fully reverse long-standing sleep debt.

Warning Signs of Sleep Debt

Common indicators include:

reliance on caffeine
difficulty waking up
daytime drowsiness
poor focus
frequent illness

Persistent symptoms require lifestyle correction.

Practical Strategies to Reduce Sleep Debt

Maintain a Consistent Sleep Schedule

Go to bed and wake up at the same time daily.

Limit Screen Exposure Before Bed

Blue light suppresses melatonin production.

Create a Sleep-Friendly Environment

Dark, quiet and cool environments improve sleep quality.

Manage Stress

Relaxation techniques reduce cortisol levels and support sleep.

Avoid Heavy Meals and Caffeine at Night

These disrupt sleep cycles.

Role of Preventive Health Checkups

Screening helps detect:

hypertension
metabolic imbalance
stress-related conditions

Sleep quality assessment should be part of preventive care.

Long-Term Benefits of Adequate Sleep

Restorative sleep supports:

stable mood
strong immunity
healthy weight
improved productivity
reduced disease risk

Sleep is foundational to wellness.

Conclusion

Understanding sleep debt and its impact on the body highlights the critical role sleep plays in maintaining physical and mental health. Chronic sleep loss disrupts hormones, weakens immunity, increases metabolic risk and affects heart health. While occasional sleep loss may be manageable, consistent deprivation carries serious long-term consequences. Prioritising adequate, high-quality sleep is one of the most powerful steps toward protecting overall health and preventing chronic disease.

References

World Health Organization (WHO) – Sleep and Non-Communicable Diseases
Indian Council of Medical Research (ICMR) – Lifestyle Disorders and Sleep Patterns
National Family Health Survey (NFHS-5) – Adult Health Indicators
Lancet – Sleep Deprivation and Chronic Disease Research
NITI Aayog – Preventive Healthcare and Lifestyle Risk Factors

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