How to Know If Bleeding Is Serious

Dietrich Easter

Adults have about 5 liters of blood, but how much of that can you lose? 

We've all injured ourselves at times (even if it's just a paper cut), but it's important to be able to determine if bleeding is truly severe. 

Any kind of loss of blood is serious, and bleeding that won't stop is more serious. Where the blood is from will also make a difference, as a bad bleed from a finger isn't as serious as a bad bleed from the neck. Likewise, spurting blood is more serious than a slow oozing bleed. 

Ultimately, if bleeding isn't controlled, people will progress into irreversible shock. This usually happens after losing 2 liters of blood. 

Let's talk a little bit more about how you can know if bleeding is serious and what you can do to stop it. 


man with bleeding hands

Types of Bleeding and the Level of Seriousness 

If you're human then you've probably seen blood before. Most of us have cut our fingers, skinned our knees, or have had a nosebleed at some point. The thing is, even these small bleeds can be serious. Not only that, but many people either overestimate or underestimate how much blood they've lost. 

No amount of bleeding should be ignored. That being said, there are some types of bleeding (and conditions) that can cause an immediate life threat. Let's go over a few different types of bleeds. 

Types of bleeding (sources): 

  • Capillary bleeding 
  • Venous bleeding 
  • Arterial bleeding

  • We'll go over these types of bleeding in more depth. 

    How Serious is a Superficial (Capillary) Bleed? 

    Capillary bleeding is usually the least severe. The capillaries are the smallest blood vessels that deliver blood to the tissues throughout the body. Capillary bleeding is common when there is blunt trauma to your skin, such as skinning your knee on the asphalt. 

    This bleeding is usually more of a slow seep than a flow. Often, all that's needed is to clean the area to avoid infection and to apply a light bandage. If someone is on blood thinners, then there's a chance you'll need to apply direct pressure to stop the bleeding. 

    Now let's talk about venous bleeding. 

    How Serious is a Venous Bleed?  

    A venous bleed is blood from the veins. Now, to understand the severity of capillary, venous, and arterial bleeds, we need to understand the purpose of these blood vessels. Imagine the arteries are like a pressure washer, with pressure behind the flow and the blood has a tendency to spray or spurt out. Arteries are under pressure and carry blood directly from the heart to other parts of the body.

    The veins are more like a gentle garden hose and tend to trickle blood instead of spurt. The veins are under low pressure, and they bring blood back to the heart and lungs. 

    With that being said, a venous bleed can be very severe depending on the location, and it will require super-firm direct pressure to the site of bleeding. Usually, a pressure bandage and firm direct pressure will stop a venous bleed. 


    man experiencing types of bleeding from his hand


    How Serious is an Arterial Bleed? 

    Arterial bleeds are the most serious. Remember what we said in the last section? How arterial bleeds are similar to water spraying from a pressure washer? An arterial bleed will spurt bright red (oxygenated) blood and require super-firm direct pressure right away. 

    With an arterial bleed from a major blood vessel, a person can lose most of their blood within seconds, so it's critical to give them good first aid. Make sure you know how to apply direct pressure and how to apply a tourniquet if needed. 

    Now let's go over the severity of a bleed from different sources. 

    The Severity of Bleeding Based on Site (And How to Stop the Bleed)

    In this section, we'll talk about different places you could bleed from as well as different types of injuries and how they bleed. We'll also mention how these bleeds can be treated (first aid) and provide links to more resources on different tools to stop a bleed. 

    The severity of a bleed based on location: 

  • Hands and arms 
  • Feet and legs 
  • Neck and Groin 
  • Head (skull) and face 
  • Chest and Back 
  • Abdomen and Internal Bleeds 

  • More details below. 

    Bleeding from Hands and Arms 

    Bleeding from the hands and arms can certainly be severe, especially if an artery is severed. Some of the most vulnerable locations are the wrist and the inside of the arm. If you're alone and your arm or hand is bleeding, apply firm direct pressure with your opposite hand. You don't need to wear gloves or have a towel or anything - you can just apply pressure directly with your hand. 

    If you think you might need a tourniquet, don't hesitate to apply one. Your best bet is to place the tourniquet "high and tight," on your upper arm, even if the bleed is from your lower arm. If you can get to a hospital within two hours, there's a good chance they can save your arm. 

    man bleeding from arm

    Bleeding from Feet and Legs 

    Bleeding from anywhere on the legs can be severe. There are larger blood vessels in your legs than in your arms, leading to higher pressures and a greater likelihood that a bleed will be life-threatening. 

    Keep in mind that, on the leg, you might need two tourniquets to stop some bleeds. This could be because the bleeding is that severe, or that the person has a particularly large leg and requires more pressure. 

    Otherwise, bleeding from the leg is treated with direct pressure, pressure bandages, and a tourniquet if you feel it's necessary. 

    How do you know you need a tourniquet? If in your mind you think, "Gosh, that's a lot of blood," don't hesitate to apply the tourniquet. The worst-case scenario is that it's a false alarm, and the physicians remove the tourniquet at the ER. Don't worry about specific estimates or anything like that. If the bleeding is bad, act. 

    Bleeding from Neck and Groin 

    Bleeding from the neck and groin is tricky because you can't control it with a normal tourniquet. Bleeding from these areas is very serious, especially if the cut is deep. You'll need to hold direct pressure and possibly pack the wound with gauze. Here's some more information on wound packing and how it works to control serious bleeding. 

    You have to be careful about the person's airway in the neck area. You need to apply pressure to a bleed but be cautious about how you apply that pressure - you don't want to constrict the trachea. 

    Bleeding from the Head (skull) and face 

    The head has a lot of bleed vessels, so even small cuts can bleed a lot. If you've ever cut yourself shaving, you've probably experienced this. A superficial bleed to the head should be taken seriously; however, with good direct pressure, the bleeding should stop without causing more problems. If the cut is deeper or involves the face, it's important to go into an urgent care or ER to have it evaluated. 

    Even if the bleeding from the face isn't serious, if the cut doesn't heal properly it could leave you looking like a pirate! 

    Bleeding from Chest and Back 

    Bleeding from the chest and back should be controlled with good direct pressure. If the wound extends into the lung cavity, then you won't be able to control the bleeding from the outside - this is a serious emergency. Be sure to get the person to the hospital as soon as possible. 

    If there's a hole in the chest cavity, the person might have a sucking chest wound or be in danger of a tension pneumothorax. Keep this in mind when caring for the person. 

    Abdomen and Internal Bleeds 

    Bleeding from the abdomen is serious - but what can be more serious is unseen internal bleeding within the abdomen. If someone has a deep open abdominal wound, they will need medical care right away. If someone sustained a hard impact on the abdomen, they might have internal bleeding you cannot see, so they should still be taken to a hospital for evaluation. 

    Now let's go over some bleeding-related complications. 

    woman bandaging a bleeding wound

    Bleeding Complications to Keep in Mind 

    Sometimes, a bleed isn't just a bleed. Let's talk about a few complications to know. This list of complications will help you decide if a "mild" bleed should be upgraded to a "serious" bleed. Some people will have one or more of these conditions. 

    Bleeding complications: 

    • Cold/hypothermia: if someone is too cold it can inhibit their body's ability to clot. So if someone is injured, keep them warm!
    • Blood disorders/Anemia: People who are anemic already don't have enough hemoglobin in their blood, so any amount of blood loss can be severe. 
    • Pregnancy: Pregnant women will produce more blood than usual, as a result, serious internal bleeding might not cause changes until later. 
    • Blood thinners: Even taking a regular aspirin can have an impact on blood loss - keep this in mind when assessing a bleed. 
    • Infection risks: Finally, all bleeding is dangerous, because an open wound presents an infection risk to the patient and to those caring for them. Keep this in mind at all times. 

     Now let's go over some final words. 

    Must-have tools for your first aid kit

    It’s time to check your med kit to make sure you have the tools you need to stop a bleed. These are several first-aid kit must-haves to make sure you and your family are prepared. Keep in mind any good bleeding control kit will have a tourniquet and QuickClot gauze of some kind. 


    QuickClot Gauze

    Skinny Medic Stop The Bleed Kit

    Conclusion: How to Recognize and Stop a Serious Bleed 

    No amount of bleeding should be taken lightly. If you think to yourself, "Wow - that's a lot of blood," then the bleeding is serious. It's as simple as that. Don't be afraid to apply a tourniquet. 

    The most important thing is that you know how to apply good super-firm direct pressure to the wound, and that you know how to use a tourniquet. 

    Remember, bad bleeding can happen fast, so you need to learn how to control it fast. Even though we recommend you call 911, even waiting 3 minutes (and often longer) for an ambulance is too long. Learn to protect yourself. 

    Be sure to read this article on when you should remove a tourniquet.