In July 2023, rising US basketball star Bronny James collapsed on the court during practice and was sent to hospital. The 18-year-old athlete, son of famous LA Lakers’ veteran LeBron James, had experienced a cardiac arrest.

Many media outlets incorrectly referred to the event as a “heart attack” or used the terms interchangeably.

A cardiac arrest and a heart attack are distinct yet overlapping concepts associated with the heart.

With some background in how the heart works, we can see how they differ and how they’re related.

Understanding the heart

The heart is a muscle that contracts to work as a pump. When it contracts it pushes blood – containing oxygen and nutrients – to all the tissues of our body.

For the heart muscle to work effectively as a pump, it needs to be fed its own blood supply, delivered by the coronary arteries. If these arteries are blocked, the heart muscle doesn’t get the blood it needs.

This can cause the heart muscle to become injured or die, and results in the heart not pumping properly.

Heart attack or cardiac arrest?

Simply put, a heart attack, technically known as a myocardial infarction, describes injury to, or death of, the heart muscle.

A cardiac arrest, sometimes called a sudden cardiac arrest, is when the heart stops beating, or put another way, stops working as an effective pump.

In other words, both relate to the heart not working as it should, but for different reasons. As we’ll see later, one can lead to the other.

Why do they happen? Who’s at risk?

Heart attacks typically result from blockages in the coronary arteries. Sometimes this is called coronary artery disease, but in Australia, we tend to refer to it as ischaemic heart disease.

The underlying cause in about 75% of people is a process called atherosclerosis. This is where fatty and fibrous tissue build up in the walls of the coronary arteries, forming a plaque. The plaque can block the blood vessel or, in some instances, lead to the formation of a blood clot.

Atherosclerosis is a long-term, stealthy process, with a number of risk factors that can sneak up on anyone. High blood pressure, high cholesterol, diet, diabetes, stress, and your genes have all been implicated in this plaque-building process.

Other causes of heart attacks include spasms of the coronary arteries (causing them to constrict), chest trauma, or anything else that reduces blood flow to the heart muscle.

Regardless of the cause, blocking or reducing the flow of blood through these pipes can result in the heart muscle not receiving enough oxygen and nutrients. So cells in the heart muscle can be injured or die.

But a cardiac arrest is the result of heartbeat irregularities, making it harder for the heart to pump blood effectively around the body. These heartbeat irregularities are generally due to electrical malfunctions in the heart. There are four distinct types:

• ventricular tachycardia: a rapid and abnormal heart rhythm in which the heartbeat is more than 100 beats per minute (normal adult, resting heart rate is generally 60-90 beats per minute). This fast heart rate prevents the heart from filling with blood and thus pumping adequately
• ventricular fibrillation: instead of regular beats, the heart quivers or “fibrillates”, resembling a bag of worms, resulting in an irregular heartbeat greater than 300 beats per minute
• pulseless electrical activity: arises when the heart muscle fails to generate sufficient pumping force after electrical stimulation, resulting in no pulse
• asystole: the classic flat-line heart rhythm you see in movies, indicating no electrical activity in the heart.

Cardiac arrest can arise from numerous underlying conditions, both heart-related and not, such as drowning, trauma, asphyxia, electrical shock and drug overdose. James’ cardiac arrest was attributed to a congenital heart defect, a heart condition he was born with.

But among the many causes of a cardiac arrest, ischaemic heart disease, such as a heart attack, stands out as the most common cause, accounting for 70% of all cases.

So how can a heart attack cause a cardiac arrest? You’ll remember that during a heart attack, heart muscle can be damaged or parts of it may die. This damaged or dead tissue can disrupt the heart’s ability to conduct electrical signals, increasing the risk of developing arrhythmias, possibly causing a cardiac arrest.

So while a heart attack is a common cause of cardiac arrest, a cardiac arrest generally does not cause a heart attack.

What do they look like?

Because a cardiac arrest results in the sudden loss of effective heart pumping, the most common signs and symptoms are a sudden loss of consciousness, absence of pulse or heartbeat, stopping of breathing, and pale or blue-tinged skin.

But the common signs and symptoms of a heart attack include chest pain or discomfort, which can show up in other regions of the body such as the arms, back, neck, jaw, or stomach. Also frequent are shortness of breath, nausea, light-headedness, looking pale, and sweating.

What’s the take-home message?

While both heart attack and cardiac arrest are disorders related to the heart, they differ in their mechanisms and outcomes.

A heart attack is like a blockage in the plumbing supplying water to a house. But a cardiac arrest is like an electrical malfunction in the house’s wiring.

Despite their different nature both conditions can have severe consequences and require immediate medical attention.

Michael Todorovic, Associate Professor of Medicine, Bond University and Matthew Barton, Senior lecturer, School of Nursing and Midwifery, Griffith University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

This time of year, many of us love to get out and spend time in nature. This may include hiking through Australia’s many beautiful national parks.

Walking in nature is a wonderful activity, supporting both physical and mental health. But there can be risks and it’s important to be prepared.

You may have read the news about hiker, Hadi Nazari, who was recently found alive after spending 13 days lost in Kosciuszko National Park.

He reportedly survived for almost two weeks in the Snowy Mountains region of New South Wales by drinking fresh water from creeks, and eating foraged berries and two muesli bars.

So next time you’re heading out for a day of hiking, what foods should you pack?

Here are my three top foods to carry on a bushwalk that are dense in nutrients and energy, lightweight and available from the local grocery store.

1. Muesli bars

Nazari reportedly ate two muesli bars he found in a mountain hut. Whoever left the muesli bars there made a great choice.

Muesli bars come individually wrapped, which helps them last longer and makes them easy to transport.

They are also a good source of energy. Muesli bars typically contain about 1,500–1,900 kilojoules per 100 grams. The average energy content for a 35g bar is about 614kJ.

This may be a fraction of what you’d usually need in a day. However, the energy from muesli bars is released at a slow to moderate pace, which will help keep you going for longer.

Muesli bars are also packed with nutrients. They contain all three macronutrients (carbohydrate, protein and fat) that our body needs to function. They’re a good source of carbohydrates, in particular, which are a key energy source. An average Australian muesli bar contains 14g of whole grains, which provide carbohydrates and dietary fibre for long-lasting energy.

Muesli bars that contain nuts are typically higher in fat (19.9g per 100g) and protein (9.4g per 100g) than those without.

Fat and protein are helpful for slowing down the release of energy from foods and the protein will help keep you feeling full for longer.

There are many different types of muesli bars to choose from. I recommend looking for those with whole grains, higher dietary fibre and higher protein content.

2. Nuts

Nuts are nature’s savoury snack and are also a great source of energy. Cashews, pistachios and peanuts contain about 2,300-2,400kJ per 100g while Brazil nuts, pecans and macadamias contain about 2,700-3,000kJ per 100g. So a 30g serving of nuts will provide about 700-900kJ depending on the type of nut.

Just like muesli bars, the energy from nuts is released slowly. So even a relatively small quantity will keep you powering on.

Nuts are also full of nutrients, such as protein, fat and fibre, which will help to stave off hunger and keep you moving for longer.

When choosing which nuts to pack, almost any type of nut is going to be great.

Peanuts are often the best value for money, or go for something like walnuts that are high in omega-3 fatty acids, or a nut mix.

Whichever nut you choose, go for the unsalted natural or roasted varieties. Salted nuts will make you thirsty.

Nut bars are also a great option and have the added benefit of coming in pre-packed serves (although nuts can also be easily packed into re-usable containers).

If you’re allergic to nuts, roasted chickpeas are another option. Just try to avoid those with added salt.

3. Dried fruit

If nuts are nature’s savoury snack, fruit is nature’s candy. Fresh fruits (such as grapes, frozen in advance) are wonderfully refreshing and perfect as an everyday snack, although can add a bit of weight to your hiking pack.

So if you’re looking to reduce the weight you’re carrying, go for dried fruit. It’s lighter and will withstand various conditions better than fresh fruit, so is less likely to spoil or bruise on the journey.

There are lots of varieties of dried fruits, such as sultanas, dried mango, dried apricots and dried apple slices.

These are good sources of sugar for energy, fibre for fullness and healthy digestion, and contain lots of vitamins and minerals. So choose one (or a combination) that works for you.

Don’t forget water

Next time you head out hiking for the day, you’re all set with these easily available, lightweight, energy- and nutrient-dense snacks.

This is not the time to be overly concerned about limiting your sugar or fat intake. Hiking, particularly in rough terrain, places demands on your body and energy needs. For instance, an adult hiking in rough terrain can burn upwards of about 2,000kJ per hour.

And of course, don’t forget to take plenty of water.

Having access to even limited food, and plenty of fresh water, will not only make your hike more pleasurable, it can save your life.

Margaret Murray, Senior Lecturer, Nutrition, Swinburne University of Technology

This article is republished from The Conversation under a Creative Commons license. Read the original article.