Introduction

Hypoxia is a condition in which the body tissues and atmosphere (environment) are devoid of oxygen. This may occur in living beings and their surroundings. In living beings, hypoxia refers to the low amount of oxygen supplied to the body’s tissues, whereas hypoxia in an environmental perspective refers to the depletion of oxygen levels, especially in water bodies.

In this article, we will delve into hypoxia, its impact on living beings and surroundings, and different environmental factors instigating the hypoxic condition.

Hypoxia¹

Hypoxia is defined as an inadequate supply of oxygen to the body tissues.¹ Oxygen is crucial for normally operating body tissues, cells, and organs. Hypoxia in living beings is manifested with symptoms such as confusion, laziness, exhaustion, and difficulty in breathing. In chronic cases, hypoxia can cause organ failure and in some situations even death.

Types of hypoxia²

• Anaemic hypoxia
• Circulatory hypoxia
• Hypoxic hypoxia
• Histotoxic hypoxia

Hypoxia in environmental perspective

Hypoxia is generally related to human beings, and is also a crucial problem in the environment. The environmental hypoxia effects are most commonly seen in aquatic life bodies. Low levels of oxygen are dangerous to aquatic creatures. This leads to eutrophication,³ which means there are increased nutrients in the aquatic environment and excessive growth of simple and unwanted plants.

Eutrophication gives rise to Dead zones.⁴ Dead zones are the places or zones in aquatic environments, in which the algae are formed in excess and after decomposition, they consume all the oxygen from the aquatic environment.

Dead zones are formed due to pesticides, agricultural wastes, industrial residues, and sewage water discharge into the natural water bodies. These things promote the algae growth and when they die and decompose, they consume all the oxygen from the water bodies.

Environmental factors that promote hypoxia

1. Air pollution

Air pollution releases impurities or pollutants in the atmosphere which downgrade the air quality. This hampers the oxygen levels in the atmosphere leading to harmful health issues. People with pulmonary diseases or breathing diseases suffer more due to low oxygen supply.

2. Water pollution

Popularly described as eutrophication.³ Mainly occurs because of nutrients such as nitrogen and phosphorus released into the water bodies. 

3. High altitude environment 

The best example of hypoxia can be seen in the higher altitudes. Altitudes and oxygen levels are inversely proportional to each other. The higher the altitude, the lower the oxygen levels. This is popularly explained by the gas laws.

Air pressure decreases at higher altitudes, due to the effect of gravity. Force due to gravity is higher towards the earth’s surface, hence the air particles are pulled towards each other and air pressure increases. Therefore,  when you climb higher altitudes, air pressure decreases due to the lower force of gravity.

Due to low air pressure, symptoms such as nausea, dizziness, and headache can be observed.

4. Erosion of soil and destruction of forest 

Destruction of forests and soil erosion are collateral but are sponsored by the hypoxic conditions in the environment. The forests are destroyed by humans for their own needs, making the soil loose and causing nutrient accumulation in the neighbouring aquatic environment. This leads to lower oxygen levels in the water, giving rise to hypoxic conditions. 

5. Global warming ( particularly in the ocean )

The climate crisis or the greenhouse effect is another essential factor of hypoxic conditions. The increase in global heat levels affects aquatic life by increasing the temperature of the water. Hot water does not hold the oxygen molecules, whereas cold water holds the oxygen molecules very tightly., Hence warm water is the reason for hypoxia.

Consequences of hypoxia on human health⁵

The effects of hypoxia on health are risky and dangerous. Our body carries out normal functioning of the organs, which is done by a continuous supply of oxygen. If the supply of oxygen is reduced or stopped, the functioning of the body and mind is hampered.

Some of the symptoms of hypoxia are:

• Restlessness
• Confusion or delirium
• Dyspnea, which means shortness of breath
• Rapid and shallow breathing
• Increased heart rate
• Lethargy

If the condition is chronic, then the symptoms may worsen, such as:

• Cyanosis, which is bluish discolouration of the skin
• Drumstick fingers and clubbing of fingers are seen
• Discomfort in the chest area
• Vomiting
• Anxiety or panic attacks

Consequences of hypoxia on the environment 

Environmental hypoxia is mainly seen in aquatic life. The aquatic life creatures are migrating to oxygen-rich water bodies due to hypoxic effects.

The effects seen are:

1. Loss of biological diversity

The hypoxic condition forces the water animals to relocate resulting in disturbance in the food web and ecological community.

2. The breakdown of the entire ecological community due to their migration
3. Decrease in fish reserves

Due to hypoxic conditions, either the fish die or migrate to other water bodies, creating difficulties for people whose livelihood depends on the fish trade.

Summary 

Hypoxia is a condition in which low levels of oxygen are detected. Hypoxia can be seen in humans and their surroundings (environment). Hypoxia in humans is manifested by symptoms like restlessness, confusion, breathing problems, chest pain, and in severe cases, there may be respiratory disturbances, cyanosis, and clubbing of fingers and toes. Hypoxia in the environment can be seen in aquatic environments with consequences such as loss of ecological biodiversity due to the immigration of aquatic organisms from low oxygen levels to oxygen-rich environments.

Hypoxia in humans occurs due to factorssuch as higher altitudes, air pollution, and respiratory disorders. Hypoxia in the environment is due to deforestation, soil erosion, accumulation of nutrients, mainly nitrogen and phosphorus in water, the greenhouse effect and abnormal rise in global heat.

It is our responsibility to reduce hypoxic conditions and protect both humans and ecosystems.