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Review of the ResMed Activox Portable Oxygen Concentrator

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If you’re a patient with an active life struggling with breathing problems, the Activox Portable Oxygen Concentrator with Pulse Dose Flow could be just what you need. In this review of ResMed Activox Portable Oxygen Concentrator, we’ll show you why this device is perfect for patients on the go.

The Activox 4L is versatile and has active users in mind. It’s portable and offers multiple hours of use time due to its internal battery. You can even pair it with the optional external battery option to further run time even more.

It provides patients with pulse dose flow with four pulse settings. Before now, the Activox only came in a unit that provided one to three liters per minute. Today, patients now have the option of four LPM, providing them with the peace of mind and freedom they want in a sturdier portable machine without any weight compromise.

It has the same dimensions as the other ResMed Activox models but weighing only five pounds, truly raising the bar with its combination of weight, size, ease of use, power and high-flow oxygen capabilities.

The Activox 4L is intended for patients who’re are diagnosed as requiring and prescribed supplemental oxygen. It offers high concentration, supplemental oxygen to patients at home, travel environments and institutions.

Lightweight, Compact with Pulse Dose Flow

The measurements of the Activox concentrator are 9.05″ x 7.875″ x 4.38″. With the integrated battery in the concentrator body, the overall size of the unit is extremely compact. Since there’s an integrated battery, you can unplug the concentrator and take it and the other accessories and supplies wherever you go.

One to Four LPM Pulse Dose Flow

The Activox offers pulse dose flow of oxygen, helping extend the life of the battery of the concentrator as opposed to continuous flow. During inhalation, the user receives pulse oxygen from the pulse dose flow, helping avoid wasted oxygen. You can set the concentrator levels from one to four LPM.

The unit has Pulse Wave delivery technology that the user can trigger on demand during inhalation. As you breathe, the Pulse Wave Breath Detection Symbol flashes confirming the machine is delivering an oxygen dose with each breath you inhale. If you stop breathing into the nasal cannula, the 4L machine begins delivering oxygen doses automatically and continues to provide oxygen doses automatically until you resume normal breathing.

Unlike the usual pulse dose delivery which may deliver oxygen at a quicker rate than you can inhale, the Pulse Wave technology helps match the delivery of oxygen to your inhalation rate for synchrony and comfort. It also reduces retrograde airflow, decreasing side effects.

Other Features of the Activox

Other features of the Activox 4L portable oxygen concentrator are:

Auto Mode

Due to the Pulse Wave delivery and auto mode technology, the Activox can provide a source of oxygen all day and night, seven days a week.

Auto mode is a feature that detects breathing pattern changes automatically and adjusts the machine’s breath detector sensitivity to deliver oxygen during all activity levels during the day and while you rest at night.

When in “active-high” mode, the machine tailors the oxygen for frequent, short breaths you require during activity. While in “rest mode) which is a more sensitive breath detector used for identifying and providing oxygen for prolonged, shallow breathing that occurs while you rest.

Four-Way Carrying Case

The carry case comes with straps and connections for positioning the concentrator in one of four different carrying styles:

  • Waist
  • Backpack
  • Briefcase
  • Shoulder

This allows you to use the concentrator on the go without requiring a cart, so it leaves your hands free to perform other activities.

Digital Display

There’s a digital display on the Activox machine so you can view important information easily about the concentrator. On the display, you can view things like the:

  • Internal battery charge
  • The connection of optional external battery charge
  • External power connection
  • Current flow setting
  • Current messages and warnings


The Activox 4L portable oxygen concentrator is also FAA-approved, meaning it’s approved for in-flight use on both international and domestic commercial airlines, which makes it the perfect portable oxygen travel system for vacations and long trips.

Powered to Keep Up

The Activox provides you with the freedom to travel and continue activities away from your home due to its long-lasting internal battery.

You can get up to 10.25 hours of use on a single charge, which enables you to spend your day away from your home without having to worry about needing to recharge the battery. You can also recharge on the go, even while you use the device, if you require extended time away from home.

Personal Therapy

Along with its important technologies, the device includes alarm and charging notifications and advanced oxygen purity sensors so you’re always informed and set up for optimal therapeutic outcomes. You should learn your needs to personalize your therapy. With the unique Pulse Wave and auto mode delivery options, the device automatically adjusts therapy to maximize saturation while reducing any potential side effects.

Multiple Power Options

The ResMed Activox portable oxygen concentrator provides you with several power options including:

Integrated Internal Battery

As mentioned, the Activox has a unique integrated battery that’s inside the device. Unlike other devices where they only come with external batteries, this device’s internal battery may be combined with an external battery so you can use it for an extended time without having to change the batteries out. It takes around four hours to fully charge the battery if it’s completely drained. The internal battery run times, according to the manufacturer, are:

  • 10.24 hours for setting 1
  • 8.25 hours for setting 2
  • 5 hours for setting 3
  • 4 hours for setting 4

Optional External Battery

The external battery is another option you can use together with the internal battery to increase your operation time even further. It provides an extra 2.25 (on setting 4) or 4.75 (on setting 1) hours of use.

AC Power

You may use the AC power supply for 100-240V AC voltages. The power supply included is for U.S. users, but plug adapters may be used internationally.

DC Adapter

The Activox 4L comes with a DC power adapter so you can use the concentrator using battery power from a DC cigarette-lighter plug style.

Important Tips

Here are some essential tips to take note of:

Cleaning Tips

There are no external filters or parts you need to change with this unit. You just need to wipe the concentrator if it’s dirty and on the right side of the unit, there’s the intake vent that you can clean with a soft cotton swab if you notice any debris or visible lint.

Battery Tips

Be sure to fully charge the internal battery before you use it. Again, this can take up to four hours and you can view the charge level on the display of the concentrator. If you buy the optional external battery, you should connect it during the first charge and allow it to also fully charge. The charge of the external battery can also be seen on the concentrator’s display.

Considerations for the ResMed Activox (Potential Drawbacks)

Like with anything, there could be some potential drawbacks with the Activox unit. After consulting with some user reviews, we’ve listed the drawbacks that others have reported:

  • Some users reported some vibration, but its only minor
  • Some users reported a little noise, but not all users report this
  • It felt a little heavier than other units to some users, but it’s really only five pounds compared to other devices that are as heavy as 10 pounds
  • It only provides pulse flow, not a continuous flow
  • The battery takes up to four hours to charge if it’s fully drained
  • The shoulder pad could use a little more padding

Overall, most users said it was a well-designed and effective machine.


The compact, lightweight design of the ResMed Activox 4L makes it a great machine to carry around in the 4-way carrying case. It’s simple to clean and gives you multiple hours of use before you have to recharge the battery. This provides you with the freedom to continue activities away from home and the freedom to travel, while continuing to receive the oxygen you require to help you breathe.

If you require supplemental oxygen and are looking for a portable and lightweight designed oxygen concentrator rather than an oxygen tank, the ResMed Activox Portable Oxygen Concentrator is for you.

You can read more about the ResMed Activox™ Portable Oxygen Concentrator and its specifications below.

ResMed Activox™ Portable Oxygen Concentrator

  • David Repasky

    David Repasky has been using CPAP treatment since 2017 and has first-hand experience with what it's like to live with Sleep Apnea. He brings the patient's perspective to the CPAP.com blog and has received formal training in CPAP machines, masks, and equipment.

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